fix(player): advance background audio-only episodes in the backend (UR-040)

An episode played audio-only while the app was backgrounded stalled at the
episode boundary instead of advancing, and ExoPlayer parked in STATE_ENDED —
where any later play intent (lockscreen, headset, Bluetooth reconnect) replays
the ended item, surfacing as the episode randomly restarting.

End-of-playback is dispatched from two places and they disagreed. The Android
JNI callback carried the background-audio branch but can never reach it:
load_and_play sets EndReason::NewTrackLoaded at every load and nothing clears
it, so the first real end consumes it and the decision is always Stop. The call
that actually decides is the frontend's echo of the resulting PlaybackEnded into
player_on_playback_ended — and that path had no background-audio case at all, so
it started a countdown whose advance is a webview goto() that cannot start audio
while backgrounded.

Both dispatchers now share PlayerController::auto_advance_to_next_episode, so
they cannot drift apart again.

The handoff base offset moves from the BackgroundAudioOffset Tauri state onto
the controller, and the advance clears it: the next episode's stream is built
without StartTimeTicks, so its timeline is already absolute and a stale base
made player_exit_background_audio return old_base + position_in_new_episode.
Unreachable until the advance actually worked.

Tests (red before the fix):
- test_auto_advance_background_audio_episode_advances_in_backend
- test_auto_advance_foreground_video_episode_uses_countdown
- test_advance_to_next_episode_audio_only_clears_handoff_base

Bump to 0.2.9.

.gitea/workflows/traceability-check.yml

@@ -42,30 +42,45 @@ jobs:
           echo "📊 Validating requirement traceability..."
           echo ""
 
-          # Parse JSON
+          # Denominators come from docs/requirements.md at run time — NEVER
+          # hardcode them here. This step previously divided by frozen literals
+          # (UR/39, IR/24, DR/48, JA/3, total 114) while the file had grown to
+          # 211 requirements, so it reported 158% coverage and the threshold
+          # below could never trip. See docs/specs/traceability-gate-repair.md.
           TOTAL_TRACES=$(jq '.totalTraces' traces-report.json)
-          UR=$(jq '.byType.UR | length' traces-report.json)
-          IR=$(jq '.byType.IR | length' traces-report.json)
-          DR=$(jq '.byType.DR | length' traces-report.json)
-          JA=$(jq '.byType.JA | length' traces-report.json)
+          COVERED=$(jq '.coverage.covered' traces-report.json)
+          TOTAL_REQS=$(jq '.coverage.total' traces-report.json)
+          COVERAGE=$(jq '.coverage.percent' traces-report.json)
 
-          # Print coverage report
           echo "✅ TRACES Found: $TOTAL_TRACES"
           echo ""
-          echo "📋 Coverage Summary:"
-          echo "   User Requirements (UR):         $UR / 39 ($(( UR * 100 / 39 ))%)"
-          echo "   Integration Requirements (IR): $IR / 24 ($(( IR * 100 / 24 ))%)"
-          echo "   Development Requirements (DR): $DR / 48 ($(( DR * 100 / 48 ))%)"
-          echo "   Jellyfin API Requirements (JA): $JA / 3 ($(( JA * 100 / 3 ))%)"
+          echo "📋 Coverage Summary (traced / defined):"
+          for T in UR IR DR JA; do
+            TRACED=$(jq --arg t "$T" '[.byType[$t][] | select(. != null)] | length' traces-report.json)
+            DEFINED=$(jq --arg t "$T" '.defined[$t]' traces-report.json)
+            echo "   $T: $TRACED / $DEFINED"
+          done
           echo ""
 
-          COVERED=$((UR + IR + DR + JA))
-          TOTAL_REQS=114
-          COVERAGE=$((COVERED * 100 / TOTAL_REQS))
-
           echo "📈 Overall Coverage: $COVERED / $TOTAL_REQS ($COVERAGE%)"
           echo ""
 
+          # Traced IDs that requirements.md does not define (typo, or a deleted
+          # requirement). These do not count toward coverage.
+          ORPHANED=$(jq -c '.coverage.orphaned' traces-report.json)
+          if [ "$ORPHANED" != "[]" ]; then
+            echo "⚠️  Traced but not defined in requirements.md: $ORPHANED"
+            echo ""
+          fi
+
+          # A ratio above 100% means the computation is broken — the exact
+          # condition that hid the stale-denominator bug. Fail loudly.
+          if [ "$COVERAGE" -gt 100 ]; then
+            echo "❌ ERROR: Coverage ($COVERAGE%) exceeds 100% — the gate is miscomputing."
+            echo "   Orphaned IDs: $ORPHANED"
+            exit 1
+          fi
+
           # Check minimum threshold
           MIN_THRESHOLD=50
           if [ "$COVERAGE" -lt "$MIN_THRESHOLD" ]; then

CHANGELOG.md

@@ -6,6 +6,63 @@ Entries are grouped by the capability they change, not by commit. Requirement
 IDs in parentheses point at [docs/requirements.md](docs/requirements.md); the
 generated trace matrix lives in [docs/traceability.md](docs/traceability.md).
 
+## v0.2.0
+
+### ✨ Features
+
+- **Audio settings now work on Android.** The equalizer, volume normalization
+  and gapless playback controls in Settings › Audio previously rendered on
+  Android and did nothing — `ExoPlayerBackend` was the only backend that never
+  implemented `set_audio_settings`, and the trait's default silently reported
+  success while applying nothing. All three now take effect:
+  - **Equalizer** — the canonical 10-band ISO curve is resampled onto whatever
+    bands the device's equalizer actually exposes (commonly 5), by nearest
+    centre frequency.
+  - **Volume normalization** — via `LoudnessEnhancer`. Note this is a gain
+    stage, not a true EBU R128 normalizer like the Linux `dynaudnorm` path, so
+    it approximates rather than matches Linux behaviour.
+  - **Gapless playback** — honours the setting via `pauseAtEndOfMediaItems`
+    (ExoPlayer is gapless by default, so this disables it when you turn it off).
+
+  The effects re-attach automatically when ExoPlayer rebuilds its audio sink on
+  a format change, so the equalizer no longer stops applying part-way through a
+  queue. (UR-027, UR-032, UR-033 → DR-030, DR-035, DR-036, IR-004)
+
+  ⚠️ **Not yet verified on a physical device.** `AudioEffect` availability and
+  band layouts vary by device and OEM ROM; where an effect is unavailable it is
+  logged and skipped rather than crashing playback.
+
+### 📋 Documentation
+
+- **Playback backend unification investigation.** Six new specs in
+  [docs/specs/](docs/specs/) record why the playback backends cannot be unified
+  onto a single engine: every candidate (mpv, GStreamer, libVLC) fails the same
+  webview-compositing constraint, because WebKitGTK/WebView2/Android WebView each
+  own their compositor surface and native video cannot interleave with HTML.
+  Audio *can* unify; video cannot. Also specifies the Android native-video spike,
+  a Windows native audio backend, and the `libmpv2` migration.
+
+### 🐛 Corrected requirement statuses
+
+These were documented as working and were not. No behaviour changed — the docs
+were wrong.
+
+- **Crossfade (UR-031, DR-034) was marked "Done (Linux only)". It is implemented
+  nowhere**, and is architecturally blocked on mpv: its audio chain is
+  single-stream, and FFmpeg's `acrossfade` requires two inputs. Real crossfade
+  would need two libmpv instances.
+- The platform parity matrix listed crossfade as a Linux/Android gap (it is
+  neither) and omitted the equalizer (which was a genuine gap, now closed).
+- `nativeAdapter.ts` cited tauri#10152 as blocking native Android video. That
+  issue is a stale feature request; the capability shipped in September 2024.
+  What remains unproven is SurfaceView-behind-WebView compositing, now tracked
+  by a spec rather than asserted as an upstream blocker.
+
+<!--
+  Note: v0.1.3–v0.1.5 have no entries here. Their changes are in the git log
+  and docs/traceability.md.
+-->
+
 ## v0.1.2
 
 ### ✨ Features

CLAUDE.md

@@ -183,8 +183,14 @@ and [docs/build-release.md](docs/build-release.md).
   backend expand it. Single-type presentation (`itemType: "Movie"`, "this page
   shows albums") is fine; a *category → set of types* mapping in `src/` is a leak.
   `bun run check:boundary` is the tripwire; the real gate is the spec's layer
-  assignment. See [scoped-search-boundary.md](docs/specs/scoped-search-boundary.md)
-  for the incident this rule came from.
+  assignment. The canonical example lives in Rust:
+  `SearchScope::item_types()` in `repository/types.rs` expands an opaque scope the
+  frontend sends. See [scoped-search-boundary.md](docs/specs/scoped-search-boundary.md)
+  for the incident this rule came from — note the tripwire missed that leak for
+  months because the mapping was assigned to a named const rather than written
+  inline at the query, so **a green `check:boundary` is not proof**; it flags
+  item-type array literals only, not run-time-built sets or `switch`/`||`
+  taxonomy.
 
 ## Writing specs
 

Dockerfile

@@ -117,9 +117,13 @@ RUN cd src-tauri && cargo fetch && cd .. && \
 
 # Desktop packaging stages build FROM the unified registry builder image (see the
 # BUILDER_IMAGE ARG at the top), which already carries every packaging tool
-# (rpm/file for Linux, mingw-w64 + nsis + the x86_64-pc-windows-gnu rust target
-# for Windows). ONE source of dependency truth, shared with CI — no per-stage
-# apt/rustup here.
+# (rpm/file for Linux, cargo-xwin + nsis + the x86_64-pc-windows-msvc rust
+# target for Windows). ONE source of dependency truth, shared with CI — no
+# per-stage apt/rustup here.
+#
+# NOTE: Windows uses the MSVC target via cargo-xwin, NOT mingw/GNU — the GNU
+# toolchain cannot bundle an NSIS installer from Linux. See
+# scripts/build-windows-cross.sh.
 
 # Linux desktop packaging environment (deb + rpm; Arch is Dockerfile.arch).
 # Thin layer over the builder — the actual build runs at container-run time on

docs/requirements.md

@@ -41,7 +41,7 @@ For a narrative overview of the system design, see
 | UR-028 | Navigate to artist/album by tapping names in now playing view | High | Done |
 | UR-029 | Toggle between grid and list view in library | Medium | Done |
 | UR-030 | Quick genre browsing and filtering | Medium | Done |
-| UR-031 | Crossfade between audio tracks | Low | Done (Linux only) |
+| UR-031 | Crossfade between audio tracks | Low | Not implemented (blocked — see DR-034) |
 | UR-032 | Gapless playback for seamless album listening | Medium | Done (Linux only) |
 | UR-033 | Volume normalization to prevent volume jumps between tracks | Low | Done (Linux only) |
 | UR-034 | Rich home screen with hero banners, carousels, and personalized sections | High | Done |
@@ -71,6 +71,7 @@ For a narrative overview of the system design, see
 | UR-058 | On the home screen, a tap on a media card opens the item (movie/episode detail page, or the series Episode Focus View for episodes) rather than starting playback; a long-press starts "play now" after a confirm; an episode detail/focus page links back to its parent series and season (see [ux-flows.md §5B.5](ux-flows.md) and [§5B.1](ux-flows.md)) | Medium | Done |
 | UR-059 | Skipping to the next episode records the episode left behind as **fully watched** rather than saving a mid-episode resume point — skipping means "done with this one", not "stopped here" — and Continue Watching hides episodes the viewer has already moved past (a partial position behind that series' next-up episode), so the row only ever offers genuinely unfinished media | Medium | Done |
 | UR-060 | Search results are ordered by how well they match: a name that *starts* with the query outranks one matching mid-word (typing "parks" finds "Parks and Recreation" before "Sparks of Love"), and at equal match quality a container outranks its contents (a series before its episodes). Results are grouped into distinct categories — TV Shows, Episodes, Movies, Songs, Albums, Artists and People — so a show never competes with its own episodes for the same slot, and searching an actor's name reaches their bio | High | Done |
+| UR-061 | Double tapping the video skips within it — right half jumps **forward 30 seconds**, left half jumps **back 10 seconds** — with an on-screen indicator naming the amount. A double tap leaves the play state unchanged — playing jumps and keeps playing, paused jumps and stays paused — because the second tap re-toggles what the first tap toggled (see DR-098); the skip lands relative to the position the player actually reports, and repeated double taps accumulate rather than all skipping from the same spot | Medium | Done |
 
 ---
 
@@ -192,7 +193,7 @@ Internal architecture, components, and application logic.
 | DR-031 | Clickable artist/album links in now playing view | UI | UR-028 | Done |
 | DR-032 | List view option for library browsing (albums, artists) | UI | UR-029 | Done |
 | DR-033 | Genre browsing screen with quick filters | UI | UR-030 | Done |
-| DR-034 | Crossfade engine with configurable duration (0-12s) | Player | UR-031 | Done (Linux only) |
+| DR-034 | Crossfade engine with configurable duration (0-12s) | Player | UR-031 | Not implemented (blocked on MPV: single-stream audio chain; `acrossfade` needs 2 inputs — see docs/specs/playback-backend-unification.md) |
 | DR-035 | Gapless playback between sequential tracks | Player | UR-032 | Done (Linux only) |
 | DR-036 | Volume normalization with preset levels (Loud/Normal/Quiet) | Player | UR-033 | Done (Linux only) |
 | DR-037 | Remote session browser and control UI | UI | UR-010 | Done |
@@ -219,7 +220,7 @@ Internal architecture, components, and application logic.
 | DR-060 | Multi-server store and active-account selection: save/get/delete server, save/get user, set/get active user (per-server), active-session resolution | Storage | UR-047 | Partial (store done; server-switcher UI pending) |
 | DR-061 | Episode Focus View: episode hero followed *immediately* by the "More Episodes" strip — a forward-biased window (~3 before / ~6 after) around the current episode, spanning season boundaries in series order, with the current episode present and badged, per-card resume progress and watched state, and click-to-swap focus (no playback) | UI | UR-048 | Done |
 | DR-062 | Detail-page section ordering: continuation content precedes discovery content — Episode Focus View renders hero → episode strip → cast → similar; Series renders hero → seasons/episodes → cast → similar | UI | UR-048 | Done |
-| DR-063 | Search scope resolver mapping the originating route to an `includeItemTypes` set (All / Music / Movies / TV), defaulting to All for Home, `/library`, and the search tab | UI | UR-049 | Implemented |
+| DR-063 | Search scope taxonomy owned by Rust: `SearchScope` (All / Music / Movies / TV) crosses IPC as an opaque enum and `SearchScope::item_types()` expands it to Jellyfin item types, resolved once in `repository_search` before the cache and server paths diverge so online and offline filter identically; `All` expands to *no* filter rather than the union of the other scopes (which would drop People and folders). The frontend maps the originating route to a scope (`resolveSearchScope`, presentation) and never names an item type for search | Backend | UR-049 | Implemented |
 | DR-064 | Scope chip row rendered under the search bar on both the search page and the in-library header search: preselected from context, horizontally scrollable, re-runs the search preserving the query on change | UI | UR-049 | Implemented |
 | DR-065 | Thread `SearchOptions.includeItemTypes` through `library.search()` so the global/header search honours scope (backend online + offline paths already support it) | UI | UR-049 | Implemented |
 | DR-066 | Persisted search result group order with a drag-and-drop settings list, keyboard-accessible reordering, a shipped default (see DR-091 for the current group set and order), and empty-group omission | Settings | UR-050 | Implemented |
@@ -245,6 +246,14 @@ Internal architecture, components, and application logic.
 | DR-089 | Continue Watching suppresses resume entries superseded by Next Up: an in-progress episode whose series has a next-up entry strictly later in series order (season, then episode) is dropped from the Home and TV rows; movies, series without a next-up entry, and items with unknown/mixed episode ordering are always kept | UI | UR-059 | Done |
 | DR-090 | Relevance ranking in Rust (`domain/search_rank.rs`): results sort by match position (prefix → word-start → mid-word substring → no name match) then by media kind (containers before their contents), stably so the backend's own relevance breaks ties. Applied in `repository_search` to both the instant cache result and the merged cache+server union, so the list does not reshuffle when server results land | Backend | UR-060 | Done |
 | DR-091 | Search result groups split TV into separate Shows and Episodes groups and add a People group (default order: Shows → Episodes → Movies → Songs → Albums → Artists → People); a stored `tvShows` order from before the split expands in place to shows+episodes so an upgrading user keeps their arrangement | UI | UR-060 | Done |
+| DR-092 | Video tap gestures resolve in `tapGestures.ts` (pure, unit-tested) rather than inline in `VideoPlayer.svelte`: `registerTap` classifies each tap and the component acts on it immediately — `togglePlayPause` for a first tap, or `seek` (+30 s right / −10 s left) plus a re-toggle for a second tap inside `DOUBLE_TAP_WINDOW_MS` (300 ms). A consumed pair resets the state, and a swipe forgets the tap. The deferral this originally used was removed in DR-098, which also covers suppressing the compatibility `click` the browser synthesizes after a touch tap. `resolveSeekTarget` converts the delta to the absolute position the facade requires, clamped per DR-095 and chained off a still-in-flight `pendingSeekTarget` so back-to-back skips accumulate instead of all resolving against a not-yet-updated position | UI | UR-061 | Done |
+| DR-094 | Frontend boundary tripwire (`scripts/check-frontend-boundary.sh`) detects Jellyfin item-type array literals **anywhere** in `src/` rather than only inline at an `includeItemTypes:` query site, so a category→type mapping cannot evade the check by being assigned to a named const (the evasion that let the `scoped-search` leak pass CI); requires two adjacent type literals so single-type presentation and `item.type ===` inspection stay legal, and caps the allowlist to force taxonomy into Rust instead of accumulating exceptions | Tooling | - | Done |
+| DR-098 | Video tap gestures act **immediately** — no deferral, no timer, and only first/second taps exist. A first tap toggles play/pause; a second tap inside `DOUBLE_TAP_WINDOW_MS` seeks *and* toggles again, so the two toggles cancel and a double tap preserves the play state (playing → jump and keep playing; paused → jump and stay paused). This replaces a design that deferred the first tap behind a 300 ms timer so a second tap could cancel it: the timer cleared its own handle *before* invoking the toggle, which reopened the `tapTimeout !== null` guard in `handleVideoClick` meant to suppress the compatibility `click` Android's WebView synthesizes after a touch — the late click then toggled a second time, producing a pause/unpause loop (long-press was unaffected, which is what identified the tap path). Click suppression no longer depends on the timer: `handleVideoClick` ignores `detail === 0` *and* any click within `TOUCH_CLICK_SUPPRESS_MS` of a touch tap. A swipe undoes the touchstart toggle exactly once (latched on `swipeGestureActive`) so brightness swipes never change play state. Click suppression is shared by **every** click target layered over the video via `isSynthesizedTouchClick`, not just the `<video>`: pausing renders a full-screen play-overlay button, so the synthesized click lands on *that* and an unguarded handler there resumed immediately — pausing appeared impossible while unpausing worked, because unpausing removes the overlay | UI | UR-061 | Done |
+| DR-099 | The video seek bar is usable by touch. Two Android-only defects made dragging or tapping it move the thumb without moving playback. (a) *Gesture hijack*: the container-level gesture layer skips `touchstart` on a control (DR-098) but kept handling `touchmove`, so a seek-bar drag was measured against the **previous** gesture's start point — a huge bogus vertical delta that read as a brightness swipe, dimmed the screen to the 0.3 floor, and fired a spurious play/pause "correction" mid-drag. A gesture is now latched at `touchstart` (`playerGestureActive`) and `touchmove` ignores anything not latched, since re-checking the move target cannot recover a start point that was never recorded. (b) *Commit signal*: the seek was committed **only** from `change`, which Android's WebView does not reliably fire for a touch interaction on a range input — the thumb moved to the tapped position and no seek ever ran. `touchend`/`mouseup` now commit as well; `input` arms a one-shot latch so whichever release signal arrives first commits and the other is a no-op. `seekRelative` shares the same `commitSeek` entry point instead of fabricating a synthetic `change` event | UI | UR-005, UR-061 | Done |
+| DR-097 | Transport authority (play/pause/toggle) lives in Rust for **webview-rendered** media, not just native. The controller tracks the state the HTML5 element reports (`html5_playing`, fed by `report_html5_state`, which now *stores* rather than only re-emitting); `play`/`pause`/`toggle_playback` consult it and drive the element by emitting a `ControlCommand` that `playerEvents.handleControlCommand` executes against the active adapter. A `stopped`/`idle` report clears it so the native backend (MPV/ExoPlayer) regains authority for music. The frontend facade no longer short-circuits transport into the adapter: `adapter.toggle()` previously decided play-vs-pause by reading `el.paused` off the DOM, a value that flips transiently while an element buffers or settles a seek — so two intents ~150 ms apart read *different* values, performed *opposing* actions, and self-sustained a play/pause loop needing no further input (observed on Android with a fully-buffered `readyState=4 networkState=1` element). Same "backend decides, adapter executes the primitive" split as `player_seek_video` | Player | UR-005 | Done |
+| DR-096 | `Html5PlayerAdapter.play()` is resilient to stall recovery: an in-flight attempt is memoised so concurrent callers (UI plus hls.js gap-controller recovery) share one `element.play()` instead of stacking calls, and an `AbortError` ("play() request was interrupted by a call to pause()") is logged at debug rather than pushed to `host.onError`. The browser raises it whenever a pending play promise is superseded by a pause/seek/source change, which hls.js does routinely while nudging past a stall — reporting it surfaced a player error roughly once per second for the whole stall and left the UI stuck showing paused | Player | UR-005 | Done |
+| DR-095 | Seek targets clamp strictly *inside* the media (`clampSeekTarget`, `END_SEEK_MARGIN_SECONDS` = 6 s ≈ one HLS segment) instead of to the exact `duration`. Landing on the duration makes hls.js request the segment whose start time lies past the end of the media (e.g. a 6330.324 s item → segment 1055 starting at 6336.33 s), which Jellyfin never produces; the fetch times out and hls.js' gap-controller stalls at the last buffered position, presenting as "unpausing or skipping bounces straight back to paused". Applied on both seek paths — the relative-skip `resolveSeekTarget` and the seek-bar drag, whose range input `max` is the duration itself — and floored at 0 so media shorter than the margin still seeks to the start | UI | UR-061 | Done |
+| DR-093 | Traceability coverage gate derives its requirement denominators from `requirements.md` at run time rather than hardcoded literals: `countDefinedRequirements` counts an ID only where it leads a markdown table row (ignoring the "Traces To" column and prose) and deduplicates IDs listed both in the definition tables and in the §3 traceability matrix; `computeCoverage` reports the *intersection* of traced and defined IDs so an ID traced in code but absent from `requirements.md` is surfaced as `orphaned` instead of inflating the ratio past 100%. UT/IT test identifiers are excluded as a separate taxonomy. CI and `bun run traces:coverage` share this computation and fail on both a sub-threshold and an impossible >100% result | Tooling | - | Done |
 
 ---
 
@@ -313,6 +322,7 @@ Internal architecture, components, and application logic.
 | UR-057 | - | DR-086 |
 | UR-058 | - | DR-087 |
 | UR-060 | - | DR-090, DR-091 |
+| UR-061 | - | DR-092 |
 
 ---
 
@@ -383,6 +393,7 @@ Internal architecture, components, and application logic.
 | UT-059 | Audio-only stream URL builder for a video item (selected audio-stream index) | JA-032, DR-052 | Pending |
 | UT-060 | Background-audio handoff state machine (background→audio, foreground→video; no dual audio) | DR-052 | Pending |
 | UT-061 | Background-audio Tauri command param naming (camelCase) | DR-052 | Pending |
+| UT-062 | `setBackgroundAudioEnabled` reports whether the native bridge was actually reached (missing bridge, stale proxy, throwing method) so a dead bridge cannot look armed | UR-040, IR-025, DR-051 | Done |
 | UT-067 | Offline `get_items` gates the synced-catalog UNION on the catalog-browse flag (downloads only when off, full catalog when on) | DR-078 | Done |
 | UT-068 | Catalog visibility resolves to `serverReachable \|\| showServerCatalog`, and is pushed to the backend on every change of either input | DR-078, DR-079 | Done |
 | UT-069 | `isConnected` follows backend reachability alone: false when the server is unreachable on a live link, true for a reachable server while `navigator.onLine` is false | DR-079 | Done |
@@ -402,6 +413,13 @@ Internal architecture, components, and application logic.
 | UT-082 | EQ fields serialize as camelCase (`equalizerEnabled`/`equalizerBands`) and round-trip | DR-030 | Done |
 | UT-083 | EQ filter entries are empty when disabled or when the curve is flat (clears the `af` filter) | IR-020 | Done |
 | UT-084 | Enabled EQ builds one peaking `equalizer` per non-zero band at the right frequency and gain inside a single `lavfi` chain | IR-020 | Done |
+| UT-085 | A first tap resolves to `togglePlayPause` immediately — no deferral and no timer | DR-092, DR-098 | Done |
+| UT-086 | A second tap inside the window seeks (+30 s right half, −10 s left half) with the matching feedback side **and** re-toggles play/pause, so the two toggles cancel and the play state is unchanged by a double tap | DR-092, DR-098 | Done |
+| UT-087 | A tap after the window, and the tap following a consumed pair, are each fresh first taps that toggle (there is no third-tap case); repeated double taps keep seeking; `cancel()` makes the next tap a first tap so an interpreted swipe cannot seek | DR-092, DR-098 | Done |
+| UT-088 | `resolveSeekTarget` applies the delta to the reported position, clamps into `[0, duration - END_SEEK_MARGIN_SECONDS]`, chains off an in-flight pending target so rapid skips accumulate, and ignores that target once the player reports past it | DR-092, DR-095 | Done |
+| UT-089 | A touch drag on the video seek bar seeks to the dragged position, never toggles play/pause, and never alters brightness — the container gesture layer stays out of a control drag entirely | DR-098, DR-099 | Done |
+| UT-090 | The seek bar commits its seek on `touchend` even when the engine never fires `change`, and commits exactly once when both signals arrive | DR-099 | Done |
+| UT-091 | Transport intents (play/pause/toggle) reach the backend even while a video adapter is registered, and never call the adapter's own `play`/`pause`/`toggle` — the webview must not decide play-vs-pause from the DOM | DR-097 | Done |
 
 ### Integration Tests
 
@@ -491,22 +509,36 @@ The `PlayerBackend` trait defines optional audio settings methods with default e
 | Basic playback | ✅ | ✅ | Parity |
 | Volume control | ✅ | ✅ | Parity |
 | Seek | ✅ | ✅ | Parity |
-| Crossfade | ✅ | ❌ | Gap |
-| Gapless playback | ✅ | ❌ | Gap |
-| Volume normalization | ✅ | ❌ | Gap |
+| Crossfade | ❌ | ❌ | Not implemented (blocked on MPV) |
+| Gapless playback | ✅ | ⚠️ | Implemented, pending on-device verification |
+| Volume normalization | ✅ | ⚠️ | Implemented (LoudnessEnhancer — gain stage, approximate vs MPV's dynaudnorm), pending on-device verification |
+| Equalizer (10-band) | ✅ | ⚠️ | Implemented (resampled onto device bands), pending on-device verification |
 | Position updates | 250ms | On-demand | Inconsistent |
 
-**Future Fix**:
-1. Implement `set_audio_settings()` in `ExoPlayerBackend`
-2. Add Kotlin-side ExoPlayer configuration for crossfade (using `ConcatenatingMediaSource` or `DefaultMediaSourceFactory`)
-3. Implement gapless via ExoPlayer's built-in gapless support
-4. Add volume normalization via ExoPlayer's `LoudnessEnhancer` or audio processor
-5. Standardize position update frequency across platforms
+**Status** (see docs/specs/android-audio-settings-parity.md):
+1. ✅ `set_audio_settings()` implemented in `ExoPlayerBackend` (JSON over JNI)
+2. ✅ Gapless via ExoPlayer's `pauseAtEndOfMediaItems`
+3. ✅ Volume normalization via `LoudnessEnhancer`
+4. ✅ Equalizer via `android.media.audiofx.Equalizer`, canonical 10 bands
+   resampled onto the device's band centres
+5. ⬜ **Not yet verified on a physical device** — the EQ/normalization effects
+   depend on device-specific `AudioEffect` availability and band layouts
+6. ⬜ Flip the trait's `set_audio_settings` default from `Ok(())` to
+   `Err(not_implemented())` so a backend that omits it fails loudly instead of
+   silently reporting success. Deferred until (5) confirms the Android path works
+7. ⬜ Standardize position update frequency across platforms
+
+Crossfade is deliberately absent: it is unimplemented on every platform and
+architecturally blocked on MPV, so building it on Android alone would invert the
+parity gap. (The previously suggested `ConcatenatingMediaSource` is also
+deprecated in current Media3.)
 
 **Impact**:
 - Medium - Android users lack audio enhancement features advertised in requirements
 - User experience differs between platforms
-- UR-031 (Crossfade), UR-032 (Gapless), UR-033 (Normalization) only work on Linux
+- UR-032 (Gapless), UR-033 (Normalization) and UR-027 (Equalizer) are now
+  implemented on Android as well as Linux, pending on-device verification
+- UR-031 (Crossfade) works nowhere — see DR-034
 
 **Traces To**: IR-004, UR-031, UR-032, UR-033, DR-034, DR-035, DR-036
 

docs/specs/android-audio-settings-parity.md

@@ -0,0 +1,209 @@
+# Spec: Android audio settings parity (EQ, normalization, gapless)
+
+**Status:** Proposed
+**Requirements:** UR-031, UR-032, UR-033, UR-027 → DR-034, DR-035, DR-036, DR-030; IR-004
+**UX spec:** n/a — no UI change; Settings › Audio already renders these controls
+**Supersedes / revises:** closes the audio half of the parity gap recorded in [playback-backend-unification.md](playback-backend-unification.md)
+
+## Summary
+
+Implement `set_audio_settings` / `audio_settings` on `ExoPlayerBackend` so the
+equalizer, volume normalization, and gapless playback settings actually take
+effect on Android. Today the Settings › Audio panel renders these controls on
+Android and they silently do nothing — `ExoPlayerBackend` is the only backend
+that does not override the trait's no-op defaults.
+
+Crossfade is explicitly **not** included; see Out of scope.
+
+## Motivation
+
+`PlayerBackend` declares `set_audio_settings` with a default `Ok(())` body.
+`MpvBackend`, `NullBackend`, and `WebviewAudioBackend` all override it;
+`ExoPlayerBackend` does not. The settings are persisted, pushed to the backend on
+every track load, and displayed in the UI — and then dropped on the floor.
+
+This is the single most user-visible platform divergence in the app: a user who
+sets a "Rock" EQ preset on Android sees the sliders move and hears no change.
+
+The backend-unification investigation ruled out fixing this by swapping engines
+(video cannot be unified; see the sibling spec), so the fix is to implement the
+trait methods where they are missing.
+
+## Layer assignment
+
+| Logic / responsibility | Layer | Why it belongs there |
+|------------------------|-------|----------------------|
+| Band count, centre frequencies, gain range, preset→curve map | Rust (existing) | Already domain-owned in `settings.rs` per [audio-equalizer.md](audio-equalizer.md). Android must consume the same `AudioSettings`, not define its own bands. Duplicating the band layout in Kotlin would be a taxonomy leak of exactly the kind `check:boundary` guards against. |
+| Mapping `AudioSettings` → Android audio-effect parameters | Rust → JNI boundary | Platform playback detail, the direct analogue of `build_af_filter` in `mpv_backend.rs`. Belongs with the other `set_audio_settings` code. |
+| Attaching/detaching `Equalizer` and `LoudnessEnhancer` to the ExoPlayer audio session | Kotlin (`JellyTauPlayer.kt`) | Android platform API mechanics; needs the live `audioSessionId`, which only the Kotlin layer holds. |
+| Normalization preset (Loud/Normal/Quiet) → target gain | Rust (existing) | `VolumeLevel` is domain vocabulary; the same preset must mean the same loudness on every platform. |
+| Rendering sliders / preset chips | Frontend (existing) | Pure presentation; unchanged by this spec. |
+
+Borderline row: attaching the effects could arguably be driven entirely from
+Rust via JNI property calls. It goes to Kotlin because `AudioEffect` construction
+requires the audio session id and must be re-attached when ExoPlayer rebuilds its
+audio sink — lifecycle state that lives in `JellyTauPlayer.kt`. Rust still owns
+*what* the values are; Kotlin owns *when* the effect objects exist.
+
+## Design
+
+### Rust — `ExoPlayerBackend` (`src-tauri/src/player/android/mod.rs`)
+
+Override the two defaulted methods, mirroring the shape of the existing
+`set_audio_track` JNI call:
+
+```rust
+fn set_audio_settings(&mut self, settings: &AudioSettings) -> Result<(), PlayerError> {
+    let s = settings.clone().with_crossfade_clamped().with_equalizer_normalised();
+    // Serialize as JSON — the same pattern load() already uses for subtitles,
+    // avoiding a 6-arg JNI signature that has to change every time a field lands.
+    let json = serde_json::to_string(&s).map_err(|e| PlayerError { message: e.to_string() })?;
+    // Kotlin: fun setAudioSettings(json: String)
+    self.call_player_method_string("setAudioSettings", &json)?;
+    self.shared_state.lock_safe().audio_settings = s;
+    Ok(())
+}
+
+fn audio_settings(&self) -> AudioSettings {
+    self.shared_state.lock_safe().audio_settings.clone()
+}
+```
+
+`ExoPlayerState` gains an `audio_settings: AudioSettings` field. Note
+`ExoPlayerBackend` currently holds no such state — `position`/`state`/`volume` are
+all pushed in by JNI callbacks — so this is the first *pull*-side field. That is
+correct: audio settings are commanded downward, never reported upward.
+
+### Kotlin — `JellyTauPlayer.kt`
+
+```kotlin
+fun setAudioSettings(json: String) {
+    val s = JSONObject(json)
+    applyEqualizer(s.getBoolean("equalizerEnabled"), s.getJSONArray("equalizerBands"))
+    applyNormalization(s.getBoolean("normalizeVolume"), s.getString("volumeLevel"))
+    exoPlayer.pauseAtEndOfMediaItems = !s.getBoolean("gaplessPlayback")
+}
+```
+
+Three independent mechanisms:
+
+- **Gapless** — nearly free. ExoPlayer is gapless by default for compatible
+  formats; honouring the setting means *disabling* it when the user turns it off,
+  via `pauseAtEndOfMediaItems`. Note this only applies within a loaded playlist;
+  our queue loads one item at a time, so verify behaviour before claiming DR-035
+  on Android (see Testing).
+- **Equalizer** — `android.media.audiofx.Equalizer` bound to
+  `exoPlayer.audioSessionId`. Android's EQ exposes a device-dependent band count
+  (commonly 5) at fixed centre frequencies, which will **not** match our 10-band
+  ISO layout. Rust owns the canonical 10 bands; Kotlin resamples them onto the
+  device's bands by nearest-centre-frequency interpolation. Gains are in
+  millibels (`setBandLevel` takes mB, we store dB → ×100), clamped to the
+  device's reported `getBandLevelRange()`.
+- **Normalization** — `android.media.audiofx.LoudnessEnhancer`, also bound to the
+  audio session, `setTargetGain(mB)` derived from `VolumeLevel`. This is a gain
+  booster, not a true EBU R128 normalizer like MPV's `dynaudnorm`; parity is
+  approximate and should be documented as such rather than overclaimed.
+
+Lifecycle: build the effects lazily on first use, release them in `release()`,
+and re-attach on `onAudioSessionIdChanged` — ExoPlayer can rebuild its audio sink
+(e.g. on a format change), which invalidates effects bound to the old session.
+
+### Make the silent-failure mode impossible
+
+The trait's default is the root cause of this whole class of bug:
+
+```rust
+// backend.rs:85 — reports success while doing nothing
+fn set_audio_settings(&mut self, _settings: &AudioSettings) -> Result<(), PlayerError> {
+    Ok(())
+}
+```
+
+Android inherits this, so every EQ/normalization change on Android returns `Ok`
+and silently does nothing — the UI ships and has no effect, with no error anywhere.
+
+Once `ExoPlayerBackend` implements the methods, **change the trait default to
+`Err(PlayerError::not_implemented())`**, matching how `set_audio_track` /
+`set_subtitle_track` already behave. Any future backend that forgets to implement
+audio settings then fails loudly instead of lying.
+
+Check the call sites before flipping it: `NullBackend` overrides both methods, so
+the graceful-degradation path is unaffected, but confirm nothing treats a
+`set_audio_settings` error as fatal to playback.
+
+### Re-application on track load
+
+`PlayerController` already re-pushes `AudioSettings` per track on the platforms
+that implement it; the Android path inherits that for free once the trait methods
+exist. No controller change.
+
+### 🔴 Threading note
+
+`setAudioSettings` is invoked from Rust on whatever thread the command lands on.
+`AudioEffect` construction must not happen on the ExoPlayer application thread
+from inside a player callback — that is the re-entrancy hazard CLAUDE.md warns
+about, and the same shape as the `AutoplayDecision` deadlock. Post the work to
+the player's handler rather than doing it inline in a listener.
+
+## Out of scope
+
+- **Crossfade (UR-031 / DR-034).** Not implemented on *any* platform today, and
+  architecturally blocked on MPV (single-stream audio chain; `acrossfade` needs
+  two inputs). Implementing it on Android alone would invert the parity gap. It
+  needs its own spec and probably two player instances.
+- True EBU R128 normalization. `LoudnessEnhancer` is a gain stage; matching
+  `dynaudnorm` exactly is out of reach without a custom `AudioProcessor`.
+- Windows audio settings — see [windows-native-audio-backend.md](windows-native-audio-backend.md).
+
+## Acceptance criteria
+
+- [ ] `ExoPlayerBackend` overrides `set_audio_settings` and `audio_settings`.
+- [ ] EQ preset change on Android audibly changes playback; setting persists across track changes and app restart.
+- [ ] Normalization toggle audibly changes level; the three presets are ordered Loud > Normal > Quiet.
+- [ ] Disabling gapless produces a gap between consecutive tracks; enabling it does not.
+- [ ] Effects are released on `release()` and survive an audio-session rebuild.
+- [ ] `requirements.md` parity matrix updated: EQ and normalization ✅ Android.
+- [ ] `bun run check` and `bun run test` pass.
+- [ ] `cargo fmt` clean, `cargo clippy` clean, `bun run test:rust` passes.
+- [ ] `bun run check:boundary` passes.
+- [ ] New requirement-implementing code carries `// TRACES:` comments.
+- [ ] `bindings.ts` regenerated if Rust types changed.
+
+## Testing
+
+**Rust** (`cargo test`): `set_audio_settings` stores the sanitized settings and
+`audio_settings()` returns them — assert clamping/normalisation is applied
+(crossfade clamped to 12s, band vector normalised to `EQ_BANDS.len()`). The JNI
+call itself is not unit-testable; extract the JSON serialization into a pure
+function and test that its shape matches what the Kotlin parser expects. That
+serialization contract is the part most likely to silently break.
+
+**Kotlin**: the band-resampling function (10 canonical bands → N device bands) is
+pure arithmetic — extract it and unit-test it, including the degenerate cases of
+a 5-band device and a device reporting 10 bands.
+
+**Manual, on device** (these are the ones that actually prove it):
+1. Set Bass Boost, play a track, confirm audible change.
+2. Toggle normalization mid-track; confirm level change without a playback stall.
+3. Queue two gapless-encoded tracks, toggle the setting, confirm the gap appears/disappears.
+4. Force a format change (44.1kHz → 48kHz track) and confirm the EQ still applies afterwards — this exercises the session-rebuild re-attach.
+
+## TRACES
+
+- `ExoPlayerBackend::set_audio_settings` → `// TRACES: UR-027, UR-032, UR-033 | DR-030, DR-035, DR-036`
+- Kotlin `setAudioSettings` / `applyEqualizer` / `applyNormalization` → same IDs
+- Band-resampling helper + its tests → `DR-030 | UT-xxx`
+
+## Notes for the implementer
+
+- Read [audio-equalizer.md](audio-equalizer.md) first — it defines the canonical
+  band layout and the preset→curve rule this spec consumes. Do not redefine bands
+  in Kotlin.
+- Android source edits go in `src-tauri/android/src` (canonical tree), then run
+  `scripts/sync-android-sources.sh`. Never edit the `gen/` tree.
+- There is a **stale duplicate** `JellyTauPlayer.kt` (285 lines) at
+  `src-tauri/android/app/src/main/java/com/dtourolle/jellytau/player/` alongside
+  the real 1103-line file at `src-tauri/android/src/main/java/...`. Edit the
+  latter. Consider deleting the former as a separate change.
+- A parallel Claude session may be active — `git diff` before "repairing"
+  unexpected changes.

docs/specs/android-native-video-spike.md

@@ -0,0 +1,196 @@
+# Spec: Android native video — transparent-webview spike
+
+**Status:** Proposed (spike — timeboxed, may conclude "not viable")
+**Requirements:** IR-004, UR-003, UR-004 → DR-001, DR-023, DR-024
+**UX spec:** n/a — no intended visual change; the video surface must land exactly where the `<video>` element is today
+**Supersedes / revises:** acts on finding 2 of [playback-backend-unification.md](playback-backend-unification.md)
+
+## Summary
+
+Test whether ExoPlayer's existing `SurfaceView` video path can be composited
+behind a transparent Tauri WebView on Android. If it works, Android regains
+hardware video decoding (MediaCodec) and libass-quality ASS/SSA subtitles, both
+of which the current webview path lacks. If it does not, we document why and
+delete the dead code.
+
+This is a **spike**, not a feature commitment. The deliverable is a yes/no answer
+with evidence, plus either a working path behind a flag or a removal.
+
+## Motivation
+
+`createAdapter()` hardcodes `const effectiveKind = "html5"` and does
+`void backendKind`, discarding the `use_html5_element` value Rust computes in
+`get_player_status`. As a result:
+
+- `NativePlayerAdapter` is dead code.
+- `JellyTauPlayer.kt`'s `getOrCreateSurfaceView()` — which already calls
+  `setZOrderMediaOverlay(false)` and wires `setVideoSurfaceHolder` — is
+  unreachable.
+- Android video decodes in the WebView instead of via MediaCodec, despite
+  `CodecDetector.kt` going to the trouble of reporting hardware codec
+  capabilities back to Rust for DeviceProfile generation.
+
+The code comment in `nativeAdapter.ts:11-14` justifies this by citing
+tauri#10152 as an upstream blocker. **That justification is stale.**
+
+### Why the blocker no longer holds
+
+- tauri#10152 is open but **dead since 2024-07-01**, and it is a *feature
+  request* ("Support transparent webviews on mobile"), not a bug report about
+  compositing.
+- The capability shipped in tauri commit `27d01834` (2024-09-02) — a clippy
+  cleanup that moved `transparent()` out of the desktop-gated impl block, fencing
+  only the tao call behind `#[cfg(desktop)]`. Because it landed as unrelated
+  cleanup, nobody closed the issue.
+- The black/white-screen reports (tauri#8381, tauri#9408) were a real but
+  *different* bug: a broken JNI signature for `setBackgroundColor`, fixed in
+  **wry 0.39.4** (PR #1237). We ship wry 0.55.x.
+- Current wry calls `setBackgroundColor(0)` unconditionally on Android when
+  transparency is requested.
+
+### The honest caveat
+
+**Nobody has demonstrated SurfaceView-behind-WebView on Tauri Android.** A search
+of both `tauri-apps/tauri` and `tauri-apps/wry` issues for `surfaceview` returns
+zero results, and the one native-video Tauri plugin
+(`YeonV/tauri-plugin-videoplayer`) sidesteps compositing by launching a separate
+fullscreen Activity. Nothing upstream blocks this; nothing upstream proves it.
+Hence: spike, not feature.
+
+Note this is the *Android* question only. The equivalent Linux compositing
+problem is maintainer-declared unfixable and is **not** in scope — see the
+unification spec.
+
+## Layer assignment
+
+| Logic / responsibility | Layer | Why it belongs there |
+|------------------------|-------|----------------------|
+| Which video backend this platform uses | Rust (existing) | `get_player_status` already computes `use_html5_element`. The frontend must *consume* it, not decide it. Restoring that is the point of the spike. |
+| Surface creation, z-ordering, `setVideoSurfaceHolder` lifecycle | Kotlin | Android platform mechanics; already written in `JellyTauPlayer.kt`. |
+| Seek/audio-track *strategy* | Rust (existing) | Already returned by `player_seek_video` / `player_switch_audio_track`; `NativePlayerAdapter` executes the chosen primitive. Unchanged — this is exactly what the `PlayerAdapter` contract was built for. |
+| Positioning the surface under the video viewport | Frontend | Pure presentation/layout. **This is the risk area** — see Design. |
+
+## Design
+
+### Phase 1 — prove compositing (no app changes)
+
+Before touching the adapter factory, verify the primitive works at all:
+
+1. Set `"transparent": true` in `tauri.conf.json` for the Android build, plus
+   `html, body { background: transparent; }`.
+2. Confirm the WebView is genuinely transparent (a native view behind it is
+   visible) and that the app does not regress to a black/white screen.
+
+If this fails, stop — everything downstream is moot, and the finding is that
+Tauri Android transparency is still broken in practice despite the shipped fix.
+
+### Phase 2 — un-hardcode the factory
+
+```ts
+// src/lib/player/adapters/index.ts
+export function createAdapter({ backendKind, host, bridge }: CreateAdapterArgs): PlayerAdapter {
+  return backendKind === "native"
+    ? new NativePlayerAdapter(host)
+    : new Html5PlayerAdapter(host, bridge);
+}
+```
+
+`backendKind` comes from `get_player_status` (`VideoBackend::Native` on Android).
+Gate behind a setting — `experimentalNativeVideo`, default **off** — so a broken
+spike cannot ship as a regression. Rust already owns this decision; the flag only
+suppresses it.
+
+**Also in scope: remove the user-agent sniffing in
+`src/lib/services/webviewAudio.ts:30-41`.** It re-derives which audio backend the
+platform has from `navigator.userAgent` ("matching the Rust cfg gate", per its own
+comment) — the frontend deciding a backend fact it should be told. Same root cause
+as the hardcode above, same fix: consume the value Rust already computes. Fold it
+in here rather than leaving a second, subtler copy of the bug behind. If
+`get_player_status` does not currently expose enough to cover the audio case, add
+the field — that is backend work, and correct.
+
+### Phase 3 — surface positioning
+
+The hard part, and where this most likely fails. The webview's `<video>` element
+occupies a laid-out box; the `SurfaceView` must be positioned to match it, and
+kept matched through scroll, rotation, and mini-player transitions.
+
+Approach: the video view reports its `getBoundingClientRect()` to Rust, which
+forwards the rect to Kotlin to position the `SurfaceView`. This is the same
+"faking it" technique the ecosystem uses on desktop — acceptable here *only if*
+the video is effectively fullscreen on Android, which it is in the player route.
+
+**Explicit failure criterion**: if the surface cannot be kept aligned during
+rotation or the mini-player transition without visible artefacts, the spike fails
+and we keep HTML5. Do not ship a janky native path for a codec win.
+
+### What we gain if it works
+
+- **Hardware decode via MediaCodec** — `CodecDetector.kt` already reports
+  capabilities; the DeviceProfile would finally match what actually plays.
+- **ASS/SSA subtitles** are *not* automatic. ExoPlayer cannot render them; that
+  would require libmpv, which is a separate and much larger decision (see the
+  unification spec's engine comparison). Scope this spike to hardware decode
+  only, and do not claim subtitle improvements from it.
+
+## Out of scope
+
+- Linux native video. Maintainer-declared unfixable on WebKitGTK/Wayland.
+- Replacing ExoPlayer with libmpv on Android.
+- Windows native video.
+- Removing the HTML5 path. It stays as the default and the fallback.
+
+## Acceptance criteria
+
+The spike is **complete** when one of these is true:
+
+**Success path**
+- [ ] Transparent WebView confirmed working on a physical device.
+- [ ] `experimentalNativeVideo` off → behaviour byte-identical to today.
+- [ ] `webviewAudio.ts` no longer inspects `navigator.userAgent`; the platform's audio backend is read from Rust.
+- [ ] `experimentalNativeVideo` on → video plays via ExoPlayer/MediaCodec, correctly positioned, with working seek, audio-track switch, and subtitle selection through the existing `PlayerAdapter` contract.
+- [ ] No artefacts on rotation, background/foreground, or mini-player transition.
+- [ ] `adb shell dumpsys media.metrics` (or logcat) confirms a hardware decoder is in use.
+- [ ] Measured battery/thermal or CPU improvement over the HTML5 path on the same clip.
+
+**Failure path**
+- [ ] The blocking behaviour is documented in this spec with evidence.
+- [ ] `NativePlayerAdapter` and the unreachable `SurfaceView` code are deleted, or explicitly retained with a *correct* comment.
+- [ ] `nativeAdapter.ts:11-14` no longer cites tauri#10152.
+
+Either way:
+- [ ] `bun run check`, `bun run test`, `bun run check:boundary` pass.
+- [ ] `cargo fmt` / `cargo clippy` clean; `bun run test:rust` passes.
+
+## Testing
+
+Adapter-selection logic is pure and testable without a device: assert
+`createAdapter` returns `NativePlayerAdapter` for `backendKind: "native"` with
+the flag on, and `Html5PlayerAdapter` in every other combination — including that
+the flag off forces HTML5 even when Rust says native. That last case is the
+regression guard.
+
+Everything else is manual on-device; there is no meaningful way to unit-test
+surface compositing. Test on at least two devices — compositing behaviour varies
+by OEM and Android version.
+
+Per CLAUDE.md, if the spike turns into a bug fix (e.g. seek breaks under the
+native adapter), write the failing test first.
+
+## TRACES
+
+- `createAdapter` → `// TRACES: UR-003, UR-004 | DR-023, DR-024`
+- Adapter-selection tests → `UT-xxx`
+- No new requirement IDs; this spike either satisfies existing IR-004 expectations or documents why it cannot.
+
+## Notes for the implementer
+
+- **Do not skip Phase 1.** If transparency does not work, phases 2 and 3 are
+  wasted effort.
+- `VideoPlayer.svelte` has a documented hazard: no lifecycle calls after an
+  `await` in `onMount` — it flips to HTML5 mode and breaks Android seek. The
+  adapter swap touches exactly this code path.
+- tauri-specta tagged responses keep Rust field names (`new_url`, not `newUrl`).
+- Android source edits go in `src-tauri/android/src`, then run
+  `scripts/sync-android-sources.sh`.
+- A parallel Claude session may be active — `git diff` first.

docs/specs/audio-equalizer.md

@@ -4,6 +4,7 @@
 **Requirements:** UR-027 → DR-030 (EQ UI), IR-020 (MPV EQ integration).
 **UX spec:** n/a (extends the Settings › Audio section, ux-flows §8.1 instant-apply).
 **Supersedes / revises:** —
+**Revised by:** [android-audio-settings-parity.md](android-audio-settings-parity.md) — lifts the "Android is a no-op" limitation below.
 
 ## Summary
 
@@ -115,6 +116,10 @@ fields ride along. `NullBackend`/Android inherit the trait default (no-op).
 ## Out of scope
 
 - Android/ExoPlayer EQ (parity gap tracked with crossfade/gapless/normalize).
+  **Now specified in [android-audio-settings-parity.md](android-audio-settings-parity.md)**,
+  which implements `set_audio_settings` on `ExoPlayerBackend`. The canonical band
+  layout and preset→curve map defined here remain authoritative; the Android side
+  resamples those bands onto the device equalizer rather than defining its own.
 - Per-track or per-library EQ profiles — one global profile only.
 - Automatic loudness/room correction; only manual bands + presets.
 - Changing the crossfade/normalize TODOs in `set_audio_settings` beyond wiring

docs/specs/boundary-tripwire-hardening.md

@@ -0,0 +1,215 @@
+# Spec: Harden the frontend boundary tripwire
+
+**Status:** Implemented
+**Requirements:** DR-094
+**UX spec:** n/a — developer tooling.
+**Supersedes / revises:** revises the detection rule in
+[scripts/check-frontend-boundary.sh](../../scripts/check-frontend-boundary.sh);
+the boundary *policy* in [scoped-search-boundary.md](scoped-search-boundary.md)
+is unchanged.
+
+## Summary
+
+`bun run check:boundary` passes on a tree that contains the exact leak it was
+built to catch. It matches a multi-type array only when written **inline at the
+query site**, so assigning the same array to a named const evades it entirely —
+which is how [searchScope.ts](../../src/lib/utils/searchScope.ts) has kept a
+category→item-type mapping through every green CI run. This spec broadens the
+match to item-type array literals anywhere in `src/`, and resolves the handful
+of legitimate hits that broadening surfaces.
+
+## Motivation
+
+The current pattern is anchored to the `includeItemTypes:` key:
+
+```sh
+PATTERN='includeItemTypes:[[:space:]]*\[[^]]*,[^]]*\]'
+```
+
+The live leak is not written that way:
+
+```ts
+// src/lib/utils/searchScope.ts:29 — invisible to the tripwire
+const SCOPE_ITEM_TYPES = { music: ["MusicAlbum", "MusicArtist", "Audio", "Playlist"], … };
+```
+
+The taxonomy and the query are one indirection apart, and the grep only sees the
+query. The script's own header is admirably honest that it is "a TRIPWIRE, NOT A
+PROOF" — but the gap here is not a subtle judgment call it was designed to
+defer to human review. It is the *crudest form* of the violation, one `const`
+away from the shape it does match, in the very file the founding incident was
+written about.
+
+Broadening the pattern to any item-type array literal finds it, with a
+manageable number of other hits (measured, not estimated):
+
+| Site | Verdict |
+|------|---------|
+| `searchScope.ts:30,32` | 🔴 The leak. Removed by [scoped-search-boundary-implementation.md](scoped-search-boundary-implementation.md). |
+| `PersonDetailView.svelte:30` | Already allowlisted, with a recorded reason. |
+| `DownloadedBrowse.svelte:95` | Borderline — `["MusicAlbum","Series","Season","BoxSet"].includes(item.type)` as an "is this a container?" predicate. |
+| `GenericMediaListPage.svelte:298` | Borderline — `["MusicAlbum","MusicArtist","Audio","Playlist"].includes(config.itemType)` as a music-styling predicate. |
+| 6 hits in `*.test.ts` | Excluded; tests legitimately name types. |
+
+Four non-test sites total. This is a tractable change, not a boil-the-ocean one.
+
+## Layer assignment
+
+Tooling only — no application logic, nothing crosses IPC. The two borderline
+*application* sites do get a layer decision, below.
+
+| Logic / responsibility | Layer | Why it belongs there |
+|------------------------|-------|----------------------|
+| Detecting item-type array literals in `src/` | Build tooling (`scripts/`) | Static analysis of repo source; belongs beside the existing check. |
+| "Is this item a container?" (`DownloadedBrowse`) | **Rust** (recommended) | Containers-vs-leaves is Jellyfin structure, and the set grows when Jellyfin adds a container type — the litmus test's "yes". Prefer a `MediaItem.isContainer` boolean from the backend over a type-set predicate in a component. |
+| "Is this music content?" (`GenericMediaListPage`) | **Frontend, allowlisted** | Selects a grid *style*. It reads `config.itemType`, a value the page already declares about itself, and changes only if the UI is redesigned — the litmus test's "no". Single-type presentation is explicitly not the target of the rule. |
+
+`DownloadedBrowse` defaults to Rust per the checklist's borderline rule; see
+Out of scope for why the migration itself is deferred rather than bundled.
+
+## Design
+
+### 1. Broaden the pattern
+
+Replace the key-anchored pattern with one matching an array literal of two or
+more known Jellyfin item types, wherever it appears:
+
+```sh
+# Two or more adjacent item-type string literals inside a bracket.
+TYPES='Movie|Series|Episode|Audio|MusicAlbum|MusicArtist|MusicVideo|Season|BoxSet|Playlist|Book|AudioBook|Video|Person|Folder|CollectionFolder|TvChannel|LiveTvChannel'
+PATTERN="\[[[:space:]]*\"($TYPES)\"[[:space:]]*,[[:space:]]*\"($TYPES)\""
+```
+
+Properties worth stating, because each is a deliberate trade:
+
+- **Not anchored to any key**, so a named const, a function return, a `Record`
+  value, or an inline query all match equally.
+- **Requires two adjacent type literals**, preserving the existing and correct
+  carve-out that single-type presentation (`itemType: "Movie"`) is legitimate.
+- **Requires string literals**, so `item.type === "Audio"` (display inspection)
+  still does not match.
+- **Explicit type list**, not `[A-Z][a-z]+`, so arbitrary string arrays
+  (`["High","Low"]`, `["Songs","Albums"]`) do not produce noise.
+
+Keep `grep -rInE`, the `*.test.*` exclusion, and the allowlist mechanism as they
+are — all three work.
+
+### 2. Resolve the surfaced sites
+
+- `PersonDetailView.svelte` — already allowlisted; entry unchanged.
+- `GenericMediaListPage.svelte` — **add to the allowlist** with the reason from
+  the layer table (grid styling over a self-declared `itemType`).
+- `DownloadedBrowse.svelte` — **add to the allowlist with a `TODO` naming the
+  preferred fix** (backend `isContainer`). An allowlist entry that records a
+  known-borderline decision is honest; silently broadening the pattern to miss
+  it would not be.
+- `searchScope.ts` — **not allowlisted.** It is the leak, and
+  [scoped-search-boundary-implementation.md](scoped-search-boundary-implementation.md)
+  deletes it.
+
+### 3. 🔴 Sequencing
+
+**This spec must land after Stage 1 of
+[scoped-search-boundary-implementation.md](scoped-search-boundary-implementation.md).**
+Hardening the tripwire first turns `master` red on a violation with no fix
+available, and the only ways out are reverting the hardening or allowlisting the
+leak — the second of which is exactly how a boundary rule dies.
+
+### 4. Keep the allowlist honest
+
+The script already warns that a growing allowlist means the boundary is eroding.
+This change takes it from 1 entry to 3, which is close to that line. Add a hard
+cap so drift is caught mechanically rather than by whoever notices:
+
+```sh
+MAX_ALLOWLIST=4
+if [ "${#ALLOWLIST[@]}" -gt "$MAX_ALLOWLIST" ]; then
+  echo "❌ Allowlist has ${#ALLOWLIST[@]} entries (max $MAX_ALLOWLIST)."
+  echo "   Push taxonomy into Rust instead of appending here."
+  exit 1
+fi
+```
+
+The cap is deliberately just above the current count: the next exception forces
+a conversation instead of a one-line append.
+
+### 5. Restate the limits
+
+The header's "tripwire, not a proof" caveat stays and gets sharper. The broadened
+pattern still cannot see:
+
+- a type set built at run time (`[...musicTypes, "Playlist"]`),
+- types split across variables (`const A = "Audio"; [A, B]`),
+- taxonomy expressed as a `switch` or chained `||` rather than an array.
+
+The spec-review checklist remains the real gate. This raises the floor; it does
+not close the class.
+
+## Out of scope
+
+- **Migrating `DownloadedBrowse` to a backend `isContainer` flag.** It touches
+  `MediaItem`, `bindings.ts`, and the offline path — its own spec. Allowlisted
+  with a TODO here so it is recorded, not forgotten.
+- The scoped-search fix itself — [scoped-search-boundary-implementation.md](scoped-search-boundary-implementation.md).
+- Detecting the run-time-construction cases listed above.
+- Extending the check to Rust or Kotlin (the rule is about `src/`).
+- Changing the boundary *policy* in CLAUDE.md.
+
+## Acceptance criteria
+
+- [ ] With `searchScope.ts` reverted to its leaking form, `bun run check:boundary`
+      **fails** and names `src/lib/utils/searchScope.ts`. This is the criterion
+      that proves the fix — verify it explicitly before landing.
+- [ ] On the post-fix tree, `bun run check:boundary` passes.
+- [ ] A newly introduced `const X = ["Movie", "Series"]` in any non-test `src/`
+      file fails the check (regression test for the const-indirection evasion).
+- [ ] `itemType: "Movie"` and `item.type === "Audio"` do **not** trip the check.
+- [ ] `["High", "Low"]` and other non-item-type arrays do **not** trip it.
+- [ ] Test files are still excluded (the 6 known test hits stay silent).
+- [ ] The allowlist has exactly 3 entries, each with a written reason; a 5th
+      entry fails the check via `MAX_ALLOWLIST`.
+- [ ] The script header still states it is a tripwire, not a proof, and names the
+      evasions it cannot see.
+- [ ] `bun run check` and `bun run test` pass.
+- [ ] `bun run test:all` passes.
+
+## Testing
+
+The script is bash and has no test harness. Verify by construction — each is a
+temporary edit, run, revert:
+
+1. Reintroduce the `SCOPE_ITEM_TYPES` const → **must fail**.
+2. Add `const T = ["Movie","Series"]` to a scratch `.svelte` file → **must fail**.
+3. Add the same to a `.test.ts` file → **must pass** (exclusion holds).
+4. Add `itemType: "Movie"` → **must pass**.
+5. Add a 5th allowlist entry → **must fail** on the cap.
+
+Record the five results in the PR description. A grep-based gate that has never
+been observed failing is indistinguishable from one that cannot fail — which is
+the precise condition this whole spec exists to correct.
+
+## TRACES
+
+Allocate in `requirements.md`:
+
+- **DR-094** — "Frontend boundary tripwire detects Jellyfin item-type array
+  literals anywhere in `src/` (not only inline at an `includeItemTypes:` query
+  site), so a category→type mapping cannot evade the check via a named const;
+  allowlist is capped to force taxonomy into Rust rather than accumulating
+  exceptions." Category: Tooling. Status: Done on merge.
+
+Shell scripts carry no `TRACES:` comment convention in this repo; reference
+DR-094 in the script header comment instead.
+
+## Notes for the implementer
+
+- A parallel Claude session may be active in this repo — `git diff` before
+  "repairing" unexpected changes (CLAUDE.md §Gotchas).
+- **Land after Stage 1 of the scoped-search fix** — see §3. This is the one
+  ordering constraint that will break `master` if ignored.
+- Test the regex against the current tree *before* committing:
+  `grep -rInE "$PATTERN" src/ | grep -v '\.test\.'` should return exactly the
+  four sites in the Motivation table.
+- The `TYPES` list will need occasional extension as Jellyfin adds types.
+  That is acceptable for a tripwire — an unlisted type produces a false
+  negative, never a false positive, so the check degrades safely.

docs/specs/build-provenance.md

@@ -0,0 +1,250 @@
+# Spec: Build provenance (git describe + build profile)
+
+**Status:** Proposed
+**Requirements:** new DR-093 (build provenance surfaced in-app and in logs); no UR — this is a diagnostic capability, not a user feature
+**UX spec:** n/a — adds an About block to Settings; no new flow
+**Supersedes / revises:** —
+
+## Summary
+
+Make every build say exactly what it is. Today a running JellyTau reports no
+version at all — not in the UI, not in the logs — and the only version string in
+the tree is the hand-maintained `0.2.0` duplicated across three files.
+
+This adds a `build.rs`-generated provenance string (`git describe` + short SHA +
+dirty flag + debug/release profile), exposes it over IPC, and renders it in a new
+Settings › About block. It also removes one of the three hand-bumped version
+files.
+
+## Motivation
+
+The concrete problem: when a user reports "the equalizer does nothing on my
+device" — which is a live risk for v0.2.0, whose Android audio settings are not
+yet device-verified — there is currently no way to tell which build they are
+running. Tag? Master? A local debug build from three weeks ago? The bug report
+cannot distinguish them.
+
+Two smaller irritations this also fixes:
+
+- **Debug builds masquerade as releases.** `0.2.0` is `0.2.0` whether it came
+  from a tagged release or `bun run tauri dev`.
+- **Three files carry the version.** `package.json`, `src-tauri/Cargo.toml` and
+  `src-tauri/tauri.conf.json` must be bumped in lockstep; the release checklist
+  exists partly to stop them drifting.
+
+### What this deliberately does *not* do
+
+**The canonical version stays hand-bumped in `Cargo.toml`.** Cargo requires a
+literal semver string at manifest-parse time and cannot derive it from git. The
+same is true of `tauri.conf.json`. Attempting to source the *release* version
+from a tag trades a scripted, reviewable bump for a fragile build-time
+dependency that breaks in exactly the environment we care most about (CI, in
+Docker, from a shallow clone).
+
+So: **the release version is authored; the build provenance is derived.** They
+answer different questions — "what release is this?" versus "what commit is this
+binary actually built from?" — and only the second benefits from git.
+
+## Layer assignment
+
+| Logic / responsibility | Layer | Why it belongs there |
+|------------------------|-------|----------------------|
+| Capturing git describe / SHA / dirty state at compile time | Rust (`build.rs`) | Only the Rust build has a compile step that can shell out to git and bake the result into the binary. A frontend equivalent would report the *dev server's* state, not the shipped binary's. |
+| Degrading to a sentinel when git is unavailable | Rust (`build.rs`) | Build-environment concern. Must never fail the build — CI runs in Docker from a shallow clone. |
+| Release version (`0.2.0`) | Rust (`Cargo.toml`, authored) | Domain fact about the product, not derivable from the environment. |
+| Deciding *what a build is* (release / dev / dirty) | Rust | Domain classification. The frontend must not infer "this is a dev build" from a string shape — it renders what it is told. |
+| Rendering the About block, copy-to-clipboard | Frontend | Pure presentation. |
+
+Borderline row: the release/dev/dirty classification could be done in the
+frontend by pattern-matching the describe string. It goes to Rust because that is
+a *rule about what constitutes a release build*, and it would have to change if
+the tagging scheme changed — the litmus test in the template puts that in Rust.
+Send a typed enum, not a string for the frontend to parse.
+
+## Design
+
+### `build.rs`
+
+```rust
+fn main() {
+    emit_build_provenance();
+    tauri_build::build()
+}
+
+fn emit_build_provenance() {
+    let describe = std::process::Command::new("git")
+        .args(["describe", "--tags", "--always", "--dirty"])
+        .output()
+        .ok()
+        .filter(|o| o.status.success())
+        .and_then(|o| String::from_utf8(o.stdout).ok())
+        .map(|s| s.trim().to_string())
+        .unwrap_or_else(|| "unknown".to_string());
+
+    println!("cargo:rustc-env=JELLYTAU_GIT_DESCRIBE={describe}");
+
+    // Rebuild when HEAD moves or a ref is written, so the string does not go
+    // stale across commits. Guarded: these paths do not exist in a git-less
+    // source tarball, and emitting rerun-if-changed for a missing path would
+    // force a rebuild every time.
+    for p in [".git/HEAD", ".git/refs"] {
+        if std::path::Path::new("../").join(p).exists() {
+            println!("cargo:rerun-if-changed=../{p}");
+        }
+    }
+}
+```
+
+🔴 **`build.rs` must never fail the build.** Every git call is
+`.ok()`-swallowed; a missing git binary, a shallow clone, or a source tarball all
+yield `"unknown"`. A build that breaks because git is absent would be a worse bug
+than the one this fixes.
+
+Note the `../` prefixes: `build.rs` runs with CWD at `src-tauri/`, so the repo's
+`.git` is one level up.
+
+### The provenance type
+
+```rust
+/// TRACES: DR-093
+#[derive(specta::Type, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct BuildInfo {
+    /// Authored release version (Cargo.toml).
+    pub version: String,
+    /// `git describe --tags --always --dirty`, or "unknown".
+    pub git_describe: String,
+    /// What kind of build this is — classified in Rust, not inferred by the UI.
+    pub kind: BuildKind,
+}
+
+/// TRACES: DR-093
+#[derive(specta::Type, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub enum BuildKind {
+    /// Built from a clean, exactly-tagged commit in release mode.
+    Release,
+    /// Release-mode build that is not on a clean tag (e.g. master, or dirty).
+    Untagged,
+    /// debug_assertions build.
+    Development,
+    /// Git state unavailable at build time.
+    Unknown,
+}
+```
+
+Classification:
+
+```rust
+let kind = if cfg!(debug_assertions) {
+    BuildKind::Development
+} else if describe == "unknown" {
+    BuildKind::Unknown
+} else if describe.contains('-') {   // "v0.2.0-3-gcb79a37" or "...-dirty"
+    BuildKind::Untagged
+} else {
+    BuildKind::Release
+};
+```
+
+### Command
+
+```rust
+/// TRACES: DR-093
+#[tauri::command]
+#[specta::specta]
+pub fn get_build_info() -> BuildInfo { … }
+```
+
+No parameters, so the camelCase param rule does not apply; the struct fields do
+need `#[serde(rename_all = "camelCase")]` (above). Regenerate `bindings.ts`.
+
+Also log the provenance once at startup, next to the existing init logging —
+that is what makes a user-submitted log file self-identifying, which is most of
+the value.
+
+### Settings › About
+
+A new block at the bottom of `src/routes/settings/+page.svelte`, rendering
+version, describe string, and a badge for non-release builds. One
+copy-to-clipboard button that yields a paste-ready block for bug reports:
+
+```
+JellyTau 0.2.0 (v0.2.0-3-gcb79a37-dirty, development)
+linux x86_64
+```
+
+Platform/arch come from the existing Tauri APIs; do not shell out.
+
+### Removing one version file
+
+`tauri.conf.json`'s `"version"` field can be omitted, in which case Tauri falls
+back to the Cargo version. That takes the bump from three files to two.
+
+**Verify before adopting**: confirm the Android `versionName`/`versionCode` and
+the NSIS installer version still resolve correctly with the field absent —
+Android packaging in particular reads the Tauri config. If either regresses,
+keep the field and drop this part; it is a convenience, not the point of the
+spec.
+
+## Out of scope
+
+- Deriving the *release* version from git tags (see Motivation).
+- A build-time timestamp. It defeats reproducible builds and adds little over
+  the commit SHA.
+- CI provenance/attestation, SBOM, signing.
+- Displaying the Jellyfin server version (separate concern, already available
+  from `/System/Info`).
+
+## Acceptance criteria
+
+- [ ] `cargo build` succeeds with git absent, from a shallow clone, and from a source tarball with no `.git` — yielding `"unknown"` in each case, never a build failure.
+- [ ] A tagged clean release build reports `BuildKind::Release`; `bun run tauri dev` reports `Development`; a dirty tree reports `Untagged` (release mode) with `-dirty` in the describe string.
+- [ ] The describe string changes after a new commit without a manual `cargo clean` (rerun-if-changed works).
+- [ ] Provenance is logged once at startup.
+- [ ] Settings › About renders version + describe + build-kind badge, with working copy-to-clipboard.
+- [ ] 🔴 CI checkouts that build a shippable artifact set `fetch-depth: 0`, or their artifacts are knowingly stamped `unknown`. Currently only `publish-docs.yml` sets it; `build-release.yml` has five checkouts and `build-and-test.yml` two, all of which would report `unknown` as-is.
+- [ ] **No toolchain installed in CI** — git is already present in the builder image; nothing new is added.
+- [ ] `bun run check`, `bun run test`, `bun run check:boundary` pass.
+- [ ] `cargo fmt` clean, `cargo clippy` clean, `bun run test:rust` passes.
+- [ ] `bindings.ts` regenerated.
+- [ ] DR-093 allocated in `requirements.md`; new code carries `// TRACES:`.
+
+## Testing
+
+**Rust**: the classification is pure and must be extracted from the command as
+`classify_build(describe: &str, debug: bool) -> BuildKind` so it can be tested
+directly. Cover: `"v0.2.0"` → `Release`; `"v0.2.0-3-gcb79a37"` → `Untagged`;
+`"v0.2.0-dirty"` → `Untagged`; `"unknown"` → `Unknown`; `debug = true` → always
+`Development` regardless of describe.
+
+`build.rs` itself is not unit-testable. Verify its failure path manually by
+building with `PATH` stripped of git, and from a `git archive` tarball — both
+must succeed with `"unknown"`.
+
+**Frontend**: assert the About block renders each `BuildKind` correctly, and that
+it renders the backend-supplied kind rather than re-deriving it from the string
+(a test that passes a `Release` kind with a `-dirty` describe and asserts the
+badge follows the *kind* would catch that regression).
+
+## TRACES
+
+- `build.rs` provenance emission → `// TRACES: | DR-093`
+- `BuildInfo` / `BuildKind` / `classify_build` → `// TRACES: | DR-093`
+- `get_build_info` command → `// TRACES: | DR-093`
+- Settings About block → `// TRACES: | DR-093`
+- `classify_build` tests → `UT-BUILD-1`
+- Allocate **DR-093** in `requirements.md` ("Build provenance: git describe and
+  build profile surfaced in-app and in logs"). Next free DR at time of writing
+  is DR-093.
+
+## Notes for the implementer
+
+- Do the `build.rs` + command + logging first; the About UI is the smaller half
+  and the logging alone delivers most of the diagnostic value.
+- The `fetch-depth: 0` change is the easiest part to forget and the one that
+  makes CI artifacts useless if missed — it is why that acceptance box is
+  flagged. Weigh it per workflow: test-only jobs do not need it.
+- Do not add a build timestamp "while you are in there" — see Out of scope.
+- A parallel Claude session may be active — `git diff` before "repairing"
+  unexpected changes.

docs/specs/libmpv2-migration.md

@@ -0,0 +1,169 @@
+# Spec: Migrate to libmpv2 and declare the project licence
+
+**Status:** Proposed
+**Requirements:** UR-003 → IR-003 (revises the MPV integration); no new user-facing behaviour
+**UX spec:** n/a
+**Supersedes / revises:** dependency and licensing housekeeping identified in [playback-backend-unification.md](playback-backend-unification.md)
+
+## Summary
+
+Two related pieces of housekeeping that block or complicate later work:
+
+1. Replace the abandoned `libmpv` crate (pinned to a git branch) with the
+   maintained `libmpv2`.
+2. Add a `LICENSE` file. The project has none, which leaves its legal status
+   undefined while it links GPL-licensed libmpv.
+
+Neither changes user-visible behaviour. Both are prerequisites for
+[windows-native-audio-backend.md](windows-native-audio-backend.md).
+
+## Motivation
+
+### The dependency is dead
+
+```toml
+# src-tauri/Cargo.toml
+libmpv = { git = "https://github.com/ParadoxSpiral/libmpv-rs.git", branch = "master" }
+```
+
+- crates.io `libmpv` 2.0.1 was published **2020-09-29**.
+- The upstream repo's last commit was **2023-01-08**; nothing since was released.
+- We pin a git *branch*, so builds are not reproducible — the same lockfile-less
+  checkout can resolve differently over time, and CI has no protection if the
+  branch moves or the repo disappears.
+
+`libmpv2` (kohsine/libmpv2-rs) is a maintained fork of exactly this crate:
+6.0.0 released **2026-05-12**, ~23.5k recent downloads against the original's
+~1.1k, releases roughly quarterly since 2024.
+
+### The project has no licence
+
+There is no `LICENSE`/`COPYING` file and `src-tauri/Cargo.toml` has no `license`
+field. The project is open source and will never be commercial, so this is purely
+an omission — but it matters because we link libmpv, and "no licence" defaults to
+*all rights reserved*, which is incompatible with distributing a GPL-derived
+work.
+
+## Design
+
+### Part 1 — licence
+
+**Use GPLv3.** This is forced, not chosen:
+
+- mpv's default build is **GPLv2-or-later**, so the combined work must be
+  GPL-compatible.
+- Apache-2.0 is **GPLv2-incompatible** (patent-termination and indemnification
+  clauses) but GPLv3-compatible.
+- A scan of the dependency tree found Apache-2.0-**only** crates with no
+  alternative arm — most importantly **`tao`** (Tauri's own windowing crate),
+  plus `sync_wrapper`, `gethostname`, and `ring` (Apache-2.0 AND ISC).
+
+`tao` is unavoidable in a Tauri app, so GPLv2 is unavailable. Exercising mpv's
+"or later" option puts the combination at **GPLv3**.
+
+Actions:
+- Add `LICENSE` containing the GPLv3 text.
+- Add `license = "GPL-3.0-or-later"` to `src-tauri/Cargo.toml` and `license` to
+  `package.json`.
+- Note in the README that the binary links libmpv (GPLv2+) and FFmpeg.
+
+Because the project is open source, we use mpv's **default GPL build** — no
+`-Dgpl=false`, no LGPL FFmpeg build, and none of the LGPL §6 relinking analysis
+that a proprietary app would need. We keep VAAPI/VDPAU/X11 and every GPL FFmpeg
+filter.
+
+🔴 Never build FFmpeg with `--enable-nonfree` — that produces a binary that is
+**unredistributable under any licence**, open source or not.
+
+### Part 2 — libmpv → libmpv2
+
+```toml
+# Linux (and later Windows, per the Windows audio spec)
+libmpv2 = "=6.0.0"
+```
+
+Pin exactly: `libmpv2` has broken its API in **every** major release.
+
+Breaking changes to expect, from the changelog:
+
+| Version | Change | Impact here |
+|---|---|---|
+| 4.0.0 | Removed command helper methods — call `mpv.command(...)` directly | Low; we already use `command`/`set_property` |
+| 5.0.0 | Removed `mpv_node` support entirely (properties return strings; parse JSON yourself); `EventContext` folded into `Mpv`; `ProtocolContext` → `Protocol` | **Medium** — `start_event_loop` uses `create_event_context()`; check whether that call still exists |
+| 6.0.0 | `RenderContext::new()` → `Mpv::create_render_context()`; `'static` bound on `OpenGLInitParams`; render context now borrows `Mpv` (fixes a use-after-free) | **None** — we do not use the render API |
+
+The last row matters: we run mpv audio-only (`video = no`), so the entire render
+surface is irrelevant to us. Consider disabling the default `render` feature to
+reduce build surface.
+
+The main porting work is the event loop in `mpv_backend.rs` — `wait_event`,
+`disable_deprecated_events`, and the `FileLoaded` / `PlaybackRestart` /
+`PropertyChange` / `EndFile` handling, given 5.0.0 folded `EventContext` into
+`Mpv`.
+
+Everything else — `set_property` calls, the `af` filter graph, the 250ms position
+thread, the seek-suppression window — should port unchanged.
+
+## Layer assignment
+
+No logic moves. This is a dependency swap plus a licence file; the
+`PlayerBackend` trait boundary is untouched.
+
+| Logic / responsibility | Layer | Why it belongs there |
+|------------------------|-------|----------------------|
+| mpv event → `PlayerStatusEvent` mapping | Rust (unchanged) | Already correct; only the binding API beneath it changes. |
+
+## Out of scope
+
+- Any behaviour change. If playback behaves differently after this, that is a bug.
+- Windows support — separate spec, but this must land first.
+- Adopting the render API. We are audio-only on mpv.
+- Re-licensing decisions beyond adding the file the project already implies.
+
+## Acceptance criteria
+
+- [ ] `LICENSE` (GPLv3) present; `license` field set in `Cargo.toml` and `package.json`.
+- [ ] A full dependency-licence audit has been run (`cargo install cargo-license && cargo license`) and confirms no GPLv3-incompatible dependency. *(The scan behind this spec resolved 441 of 575 crates from the local registry cache; the remaining 134 are unverified.)*
+- [ ] `libmpv` git dependency removed; `libmpv2` pinned to an exact version.
+- [ ] Linux audio playback works identically: play/pause/seek/volume, queue advance, gapless, EQ, normalization, sleep timer.
+- [ ] Position updates still arrive at 250ms; the 150ms post-seek suppression still prevents the jump-to-zero glitch.
+- [ ] `EndFile` still emits `PlaybackEnded` only for EOF (not STOP/QUIT/ERROR) — autoplay depends on this.
+- [ ] Builder image updated if the libmpv dev package requirement changed; **no toolchain install added to any CI step**.
+- [ ] `bun run check`, `bun run test`, `bun run check:boundary` pass.
+- [ ] `cargo fmt` clean, `cargo clippy` clean, `bun run test:rust` passes.
+
+## Testing
+
+The existing `mpv_backend_test.rs` plus the `build_af_filter`,
+`eq_filter_entries`, and `normalize_filter_entry` tests are the regression net —
+they must pass unchanged, since none of them touch the binding API.
+
+The event loop has no unit tests and is where the risk concentrates. Verify
+manually on Linux:
+
+1. Play → pause → play; confirm position does not flash to 0:00 (the known
+   playing-event regression).
+2. Seek mid-track; confirm no jump-to-zero within 150ms.
+3. Let a track end naturally; confirm autoplay advances (exercises `EndFile` EOF).
+4. Press stop; confirm autoplay does **not** advance.
+5. Sleep-timer expiry; confirm it stops without triggering autoplay.
+
+Cases 3–5 are the ones most likely to break silently, and each corresponds to a
+bug already fixed once in this codebase.
+
+## TRACES
+
+- `MpvBackend` construction / event loop → existing `// TRACES: UR-003 | IR-003`, unchanged
+- No new requirement IDs; this is a dependency migration.
+
+## Notes for the implementer
+
+- Do this **before** the Windows audio backend.
+- Read the 4.0/5.0/6.0 changelogs before writing code — the crate has broken API
+  in every major release, most recently two months before this spec.
+- The crates.io `repository` field for `libmpv2` points at `kohsine/libmpv-rs`,
+  but the repo was renamed to **`libmpv2-rs`**; the old raw URLs 404.
+- `libmpv2-sys` ships pregenerated bindings and vendored headers, so no libclang
+  is needed at build time — relevant to keeping the builder image thin.
+- A parallel Claude session may be active — `git diff` before "repairing"
+  unexpected changes.

docs/specs/playback-backend-unification.md

@@ -0,0 +1,226 @@
+# Spec: Playback backend unification — findings and strategy
+
+**Status:** Accepted (analysis; no code changes)
+**Requirements:** IR-004, UR-031, UR-032, UR-033 — revises the "Platform Playback Backend Parity" issue in requirements.md
+**UX spec:** n/a
+**Supersedes / revises:** informs [android-native-video-spike.md](android-native-video-spike.md), [android-audio-settings-parity.md](android-audio-settings-parity.md), [windows-native-audio-backend.md](windows-native-audio-backend.md)
+
+## Summary
+
+This spec records the outcome of an investigation into unifying JellyTau's
+playback backends (Linux/MPV, Android/ExoPlayer, Windows/webview) onto a single
+engine with hardware acceleration everywhere. **The conclusion is that video
+cannot be unified onto a native engine, and should not be attempted.** Audio
+*can* be, and that is where the remaining specs direct effort.
+
+No code changes follow from this spec directly. It exists so the decision is
+written down with its evidence, and so a future session does not re-run the same
+investigation.
+
+## Motivation
+
+The requirements doc carries a "Platform Playback Backend Parity" issue noting
+that audio settings work on Linux but not Android, and proposing eventual
+convergence. The natural next question — "should we just run one engine
+everywhere?" — needed answering before spending effort on per-backend patches.
+
+The investigation also surfaced that several statements in requirements.md and in
+code comments are factually wrong. Those corrections are part of the deliverable.
+
+## Findings
+
+### 1. The current architecture is not what the docs describe
+
+| Platform | Audio | Video |
+|----------|-------|-------|
+| Linux | MPV (native, **audio-only**) | webview `<video>` + hls.js |
+| Android | ExoPlayer (native) | **webview `<video>` + hls.js** |
+| Windows | webview `<audio>` | webview `<video>` + hls.js |
+
+Two surprises:
+
+- **MPV never decodes video.** `mpv_backend.rs` sets `video = no` and
+  `audio-display = no` at construction. Linux video has always been the webview.
+  Correspondingly, `player_play_item` deliberately does *not* load into MPV on
+  Linux (it calls `set_current_item`, which only updates the queue).
+- **Android video is also the webview.** `createAdapter()` in
+  `src/lib/player/adapters/index.ts` hardcodes `const effectiveKind = "html5"`
+  and does `void backendKind`, discarding the `use_html5_element` signal that
+  `get_player_status` computes in Rust. `NativePlayerAdapter` is dead code, and
+  ExoPlayer's `SurfaceView` path in `JellyTauPlayer.kt` is unreachable.
+
+So video is *already* unified — on HTML5, everywhere, by accident of that
+hardcode — and on the path without hardware decoding on Android.
+
+### 2. Native video cannot be composited with a Tauri webview
+
+This is the load-bearing finding. It is **not** an mpv limitation; it defeats
+every candidate engine identically:
+
+- **mpv**: `tauri-plugin-libmpv`'s own platform table reads Linux ⚠️
+  *"Experimental. Window embedding is not working."*
+- **GStreamer** (wry discussion #284, 2024): *"Gstreamer was rendering above the
+  surface and covering all html elements."*
+- **libVLC** (tauri discussion #6343, 2024): *"I had to render the webview in a
+  child window though because vlc kept rendering on top of it."*
+
+Root cause, from Tauri maintainer amrbashir (tauri#9220, 2024-03-30):
+
+> "we are limited to using Webkit2GTK on Linux and that requires a GTK window.
+> While possible to add a GTK widget as a child X11 window inside raw X11 window,
+> this is however a bit hacky and **it is not possible on Wayland at all**."
+
+WebKitGTK, WebView2, and Android WebView each draw into their own compositor
+surface. A native video surface is either entirely above or entirely below the
+webview; it cannot interleave with HTML. Every working example in the ecosystem
+is the same hack — a separate child window position-synced to a
+`getBoundingClientRect()` div — which breaks on resize, scroll, and any UI drawn
+over the video. For JellyTau that means the controls, subtitle overlay, and
+mini-player.
+
+The most recent comment on tauri#6343 (2026-05-23) confirms it is still unsolved:
+
+> "I'm faking it and the window is not truly embedded, basically when the parent
+> moves or resizes I reset the position and size of the libmpv window to align it
+> with an HTML div."
+
+**The principle to carry forward: audio can unify on a native engine; video
+cannot, because video needs a surface and the webview owns the surface.**
+
+### 3. mpv would regress streaming quality
+
+mpv has **no adaptive bitrate**. It delegates HLS to FFmpeg's demuxer, which
+selects one variant at open time and never adapts; mpv#3548 (2016) requested ABR
+and it never landed. `--hls-bitrate` is a static picker defaulting to `max`.
+
+The webview path already has real ABR via hls.js. Moving video to mpv would be a
+**downgrade** on every platform — no graceful degradation on weak networks, and
+quality changes requiring teardown and reload.
+
+### 4. Crossfade is architecturally blocked on mpv
+
+mpv's audio chain is single-stream. FFmpeg's `acrossfade` is an `N→A` filter
+requiring two input streams, so there is no second input to feed it. Real
+crossfade needs **two libmpv instances** with manually ramped volumes. Upstream
+maintainer response (mpv#4512, closed three minutes after opening):
+
+> "No. I also find crossfading stupid and complex, so the likeliness of that
+> happening is low."
+
+GStreamer *could* do it via `audiomixer`. mpv cannot, at any reasonable cost.
+
+### 5. Engine comparison summary
+
+| Criterion | mpv | GStreamer | libVLC |
+|-----------|-----|-----------|--------|
+| Webview compositing | ❌ Linux broken | ❌ same wall | ❌ same wall |
+| Adaptive bitrate HLS | ❌ none | ✅ adaptivedemux2 | ✅ adaptive module |
+| Rust bindings | ⚠️ `libmpv2` active; our pin is dead | ✅ `gstreamer-rs` excellent | ❌ `vlc-rs` abandoned (2018) |
+| Windows cross-MSVC | ⚠️ prebuilt DLL | ❌ pkg-config vs cargo-xwin | ❌ no better |
+| Android packaging | ✅ Maven AAR (used by Findroid) | ⚠️ Cerbero/NDK, painful | ✅ mature AAR |
+| ASS/SSA subtitles | ✅ libass built in | ✅ libass | ✅ libass |
+| Crossfade | ❌ impossible | ✅ `audiomixer` | ⚠️ unclear |
+
+Every candidate fails the first row, which is the disqualifying one.
+
+### 6. Two further options ruled out
+
+**Webview `<audio>`/`<video>` everywhere** (i.e. delete the native audio backends
+too) is dead on Android: `navigator.mediaSession` is *deliberately compiled out*
+of Android WebView (Chromium CL 2613133003), so lockscreen/media-notification
+control would be impossible. Chromium has also never shipped `audioTracks`. It
+remains fine for Windows *video*, which is what we already do.
+
+**FFmpeg-direct / Rust-native** (`ffmpeg-next`, `rsmpeg`, Symphonia) is not
+close: the safe bindings do not expose hardware decode at all, `ffmpeg-next` is
+self-declared maintenance-only, and Symphonia lacks HE-AAC and gapless AAC. This
+is a multi-person-year path to reach parity with what we already have.
+
+### 7. If libmpv is ever revisited on Android
+
+Recorded so the next investigation starts from evidence rather than repeating the
+search. The `dev.jdtech.mpv:libmpv` AAR — maintained by Findroid's author, i.e.
+another Jellyfin Android client — was inspected directly:
+
+- `libmpv.so` exports the full 54-function `mpv_*` C API with **zero `Java_`
+  symbols**; JNI is a separate optional ~19 KB `libplayer.so`. So it is drivable
+  from Rust without a Java shim. (This is precisely what disqualifies libVLC,
+  whose Android video path hard-requires a Java `AWindow` jobject.)
+- ~23 MB/ABI, versus libVLC's ~46 MB/ABI.
+- 🔴 **The published AAR is built `--enable-gpl --enable-version3` — it is
+  GPLv3**, not LGPL. Fine for us (see [libmpv2-migration.md](libmpv2-migration.md)),
+  but it would be a hard constraint for anyone shipping closed source, and an
+  LGPL rebuild would be your own build to own.
+- Top unverified risk if anyone tries this: whether `libmpv2-sys` can
+  cross-compile for `aarch64-linux-android` against that prebuilt `.so`. No
+  working example of `libmpv2` on Android was found.
+
+None of this changes the verdict — the cost is the MediaSession/foreground-service
+rewrite, not the bindings.
+
+## Decision
+
+1. **Do not unify video onto a native engine.** Video stays in the webview with
+   hls.js on all platforms. This is not a compromise — it is the configuration
+   that falls out of the compositing constraint, and it is the only one that
+   gives us ABR for free.
+2. **Android native video is worth a bounded spike anyway** — not for
+   unification, but because ExoPlayer's `SurfaceView` path already exists and
+   would restore hardware decode plus ASS/SSA subtitles. See
+   [android-native-video-spike.md](android-native-video-spike.md).
+3. **Audio parity is the real gap** and is achievable without touching any of the
+   above. See [android-audio-settings-parity.md](android-audio-settings-parity.md)
+   and [windows-native-audio-backend.md](windows-native-audio-backend.md).
+4. **Migrate the dead libmpv pin** regardless of any of this. See
+   [libmpv2-migration.md](libmpv2-migration.md).
+
+## Corrections to existing docs
+
+These are factual errors found during the investigation. Fixing them is in scope
+for this spec.
+
+| Location | Says | Actually |
+|----------|------|----------|
+| `requirements.md` UR-031 (line ~44) | "Done (Linux only)" | Not implemented on any platform. |
+| `requirements.md` DR-034 (line ~196) | "Done (Linux only)" | Not implemented anywhere — `mpv_backend.rs` has a bare `// TODO: Implement crossfade via MPV audio filters if needed`. Architecturally blocked on mpv (finding 4). |
+| `requirements.md` parity matrix | Crossfade ✅ Linux / ❌ Android | ❌ / ❌ |
+| `requirements.md` parity matrix | (no EQ row) | EQ is also Linux-only — `build_af_filter`/`eq_filter_entries` exist only in `mpv_backend.rs`. Same root cause, same fix. |
+| `nativeAdapter.ts:11-14` | Native Android video "blocked upstream by tauri#10152" | tauri#10152 is a stale *feature request*, dead since 2024-07-01. The capability shipped in tauri commit `27d01834` (2024-09-02). Not a blocker. |
+
+## Layer assignment
+
+No new logic. The one boundary observation worth recording:
+
+| Logic / responsibility | Layer | Why it belongs there |
+|------------------------|-------|----------------------|
+| Which video backend a platform uses (`use_html5_element`) | Rust | Already correctly computed in `get_player_status`. The frontend currently *discards* it — that is the bug, not the design. Restoring it means the frontend consumes a backend decision rather than making its own. |
+
+## Out of scope
+
+- Any code change. This spec is analysis; the sibling specs carry the work.
+- iOS/macOS. Not current targets.
+- Replacing hls.js.
+
+## Acceptance criteria
+
+- [ ] `requirements.md` DR-034 status corrected; parity matrix updated (crossfade ❌/❌, EQ row added).
+- [ ] Stale tauri#10152 comment in `nativeAdapter.ts` corrected.
+- [ ] The four sibling specs exist and are linked from here.
+
+## Testing
+
+n/a — documentation only.
+
+## TRACES
+
+No new code. Requirement text changes only; DR-034's status line is the one
+substantive edit.
+
+## Notes for the implementer
+
+- The evidence above was gathered in July 2026. The compositing constraint has
+  been stable since 2021 (wry#284) and is maintainer-declared unfixable, so it is
+  unlikely to change soon — but if someone revisits this, tauri#6343 and wry#284
+  are the threads to re-read first.
+- A parallel Claude session may be active in this repo — `git diff` before
+  "repairing" unexpected changes.

docs/specs/playback-docs-corrections.md

@@ -0,0 +1,198 @@
+# Spec: Playback documentation corrections
+
+**Status:** Proposed
+**Requirements:** revises the status of DR-034; corrects the parity matrix in [requirements.md](../requirements.md)
+**UX spec:** n/a
+**Supersedes / revises:** implements the "Corrections to existing docs" section of [playback-backend-unification.md](playback-backend-unification.md)
+
+## Summary
+
+Fix four factual errors in the requirements doc and the player source comments,
+all found while investigating backend unification. Each claims something the code
+does not do. Small change, but they are actively misleading: two of them assert a
+feature is implemented when it is implemented nowhere, and one cites an upstream
+blocker that no longer exists.
+
+Documentation and comments only — no behaviour change.
+
+## Motivation
+
+These errors compound. DR-034 reads "Done (Linux only)", so a future session
+planning Android parity would reasonably assume crossfade exists on Linux and
+only needs porting — when in fact it is unimplemented everywhere *and*
+architecturally blocked on the engine it supposedly runs on. Likewise the
+tauri#10152 comment has been discouraging work on Android native video since the
+upstream capability shipped in September 2024.
+
+## The corrections
+
+### 1. DR-034 status is wrong
+
+`requirements.md` line ~196:
+
+```
+| DR-034 | Crossfade engine with configurable duration (0-12s) | Player | UR-031 | Done (Linux only) |
+```
+
+The code:
+
+```rust
+// src-tauri/src/player/mpv_backend.rs, in set_audio_settings
+// TODO: Implement crossfade via MPV audio filters if needed
+```
+
+That is the entire crossfade implementation. `crossfade_duration` is plumbed
+through `AudioSettings` and clamped to 0–12s, but no backend ever acts on it.
+
+**Change to:** `Not implemented (blocked on MPV — see playback-backend-unification.md)`
+
+Worth stating *why* in the requirements entry, because it is not a scheduling
+gap: mpv's audio chain is single-stream, and FFmpeg's `acrossfade` is an `N→A`
+filter needing two inputs. Real crossfade requires two libmpv instances with
+manually ramped volumes. Upstream declined the feature (mpv#4512).
+
+### 1b. UR-031 status is wrong for the same reason
+
+`requirements.md` line ~44:
+
+```
+| UR-031 | Crossfade between audio tracks | Low | Done (Linux only) |
+```
+
+Same error one level up: the *user* requirement is also marked done. Since no
+backend implements crossfade, UR-031 is not satisfied on any platform.
+
+**Change to:** `Not implemented (blocked — see DR-034)`
+
+Note line ~517 of the same file (`UR-031 (Crossfade), UR-032 (Gapless),
+UR-033 (Normalization) only work on Linux`) inherits the error — crossfade works
+nowhere, so it should read UR-032/UR-033 only.
+
+### 2. Parity matrix crossfade row is wrong
+
+```
+| Crossfade | ✅ | ❌ | Gap |
+```
+
+**Change to** `| Crossfade | ❌ | ❌ | Not implemented |` — it is not a
+platform-parity gap, it is an unbuilt feature.
+
+### 3. Parity matrix is missing the equalizer
+
+The matrix lists crossfade, gapless, and normalization but omits the EQ, which
+has the same Linux-only shape and the same root cause (`ExoPlayerBackend` not
+overriding `set_audio_settings`). `build_af_filter` and `eq_filter_entries` exist
+only in `mpv_backend.rs`; there is no equalizer code in the Android tree.
+
+**Add:** `| Equalizer (10-band) | ✅ | ❌ | Gap |`
+
+### 4. `nativeAdapter.ts` cites a stale blocker
+
+`src/lib/player/adapters/nativeAdapter.ts:11-14` states native Android video is
+blocked upstream by tauri#10152 (transparent webview / SurfaceView compositing).
+
+tauri#10152 is open but **dead since 2024-07-01**, and it is a *feature request*
+that `WebviewWindowBuilder::transparent` was desktop-only — not a report that
+compositing is broken. The capability shipped in tauri commit `27d01834`
+(2024-09-02), which moved `transparent()` into the cross-platform impl block with
+only the tao call `#[cfg(desktop)]`-fenced. It landed as a clippy cleanup, so the
+issue was never closed. Separately, the black/white-screen bug (tauri#8381,
+tauri#9408) was a broken JNI signature for `setBackgroundColor`, fixed in wry
+0.39.4; we ship wry 0.55.x.
+
+**Change to:** a comment stating the adapter is currently unreachable because
+`createAdapter` hardcodes the HTML5 kind, that transparency is no longer an
+upstream blocker, and that
+[android-native-video-spike.md](android-native-video-spike.md) tracks whether
+SurfaceView compositing actually works. Be explicit that *nobody has
+demonstrated* SurfaceView-behind-WebView on Tauri Android — nothing upstream
+blocks it, and nothing upstream proves it.
+
+### 5. Platform capability is signalled three incompatible ways
+
+Not a doc error — a real inconsistency found during the same investigation, worth
+recording here even though fixing it needs its own change.
+
+Which backend a platform uses is currently expressed three ways:
+
+1. Rust `#[cfg]` gates in `player/mod.rs` and `create_player_backend` — the truth.
+2. The `useHtml5Element` / `VideoBackend` value from `get_player_status` — which
+   the frontend discards (see the spike spec).
+3. **Frontend user-agent sniffing** in `src/lib/services/webviewAudio.ts:30-41`:
+
+```ts
+const ua = navigator.userAgent.toLowerCase();
+const isAndroid = ua.includes("android");
+const isLinux = ua.includes("linux") && !isAndroid;
+return !isAndroid && !isLinux;
+```
+
+The comment says it is "matching the Rust cfg gate" — i.e. the frontend
+re-derives a backend decision from the user-agent string and hopes it stays in
+sync. That is the frontend deciding *which backend exists*, which is domain
+knowledge, not presentation. It also breaks silently the moment a new target is
+added or a webview's UA changes.
+
+**This is a boundary leak of the same family the spec-review checklist exists to
+catch**, even though `check:boundary`'s tripwire (item-type arrays) does not
+match it. Rust already computes the answer; the frontend should consume it.
+
+Not fixed by this spec — it is behavioural, not documentation. It should be
+folded into the spike spec's factory rework, where the same
+"consume Rust's decision instead of re-deriving it" change is already in scope.
+
+### Also worth fixing while here
+
+`requirements.md` IR-004 reads "In Progress (basic playback works, audio settings
+missing)". That stays accurate until
+[android-audio-settings-parity.md](android-audio-settings-parity.md) lands, but
+the "Future Fix" list in the parity issue proposes
+`ConcatenatingMediaSource` for crossfade — **deprecated in current Media3**. Drop
+that suggestion; the modern approach is a custom `AudioProcessor`.
+
+## Layer assignment
+
+No logic. Documentation and comments only.
+
+| Logic / responsibility | Layer | Why it belongs there |
+|------------------------|-------|----------------------|
+| — | — | No logic introduced or moved by this spec. |
+
+## Out of scope
+
+- Implementing crossfade. This spec only stops claiming it exists.
+- Implementing Android audio settings — see the parity spec.
+- Running the Android video spike — see that spec.
+- Rewriting the architecture docs. `docs/architecture/05-platform-backends.md`
+  should be re-read for the same class of error, but that is a larger pass.
+
+## Acceptance criteria
+
+- [ ] DR-034 status corrected, with the blocking reason stated.
+- [ ] UR-031 status corrected (line ~44), and the "only work on Linux" line (~517) no longer lists crossfade.
+- [ ] Parity matrix: crossfade ❌/❌; equalizer row added.
+- [ ] `ConcatenatingMediaSource` suggestion removed from the "Future Fix" list.
+- [ ] `nativeAdapter.ts` comment corrected and pointing at the spike spec.
+- [ ] `bun run check` and `bun run test` pass (a comment change still touches TS).
+- [ ] `bun run traces:markdown` re-run if requirement text changed.
+
+No Rust changes, so the `cargo` gates do not apply.
+
+## Testing
+
+None beyond the standard gates — no behaviour changes. Confirm
+`bun run traces:markdown` regenerates cleanly, since DR-034's row is referenced
+by the traceability matrix.
+
+## TRACES
+
+No code implementing requirements changes; no TRACES comments to add or update.
+The DR-034 row in `docs/traceability.md` will regenerate with the corrected text.
+
+## Notes for the implementer
+
+- Do **not** silently delete DR-034. The requirement (UR-031 crossfade) is still
+  wanted; it is the *status* that is wrong. Keeping the row with an honest status
+  and a reason is the point.
+- A parallel Claude session may be active — `git diff` before "repairing"
+  unexpected changes.

docs/specs/player-facade-enforcement.md

@@ -0,0 +1,258 @@
+# Spec: Enforce the unified player boundary
+
+**Status:** Proposed
+**Requirements:** DR-095 (new); relates to UR-005 and the unified-player-boundary
+principle in CLAUDE.md and [02-svelte-frontend.md](../architecture/02-svelte-frontend.md)
+**UX spec:** n/a — refactor, no user-visible change.
+**Supersedes / revises:** n/a
+
+## Summary
+
+The stated principle is that UI controls playback **only** through
+`playerController` ([src/lib/player/index.ts](../../src/lib/player/index.ts)),
+never by calling `commands.player*` directly. There are **52 direct call sites
+outside** that facade. This spec routes the genuine playback-control calls
+through the facade, narrows the principle's wording so it stops forbidding
+things it never meant to forbid, and adds the lint rule that keeps it true —
+because this rule is the one design principle in the audit with **no automated
+check at all**, and it is also the one that drifted furthest.
+
+## Motivation
+
+Direct `commands.player*` usage outside `src/lib/player/`, by file:
+
+| File | Sites |
+|---|---|
+| [queue.ts](../../src/lib/stores/queue.ts) | 10 |
+| [player/[id]/+page.svelte](../../src/routes/player/[id]/+page.svelte) | 9 |
+| [VideoPlayer.svelte](../../src/lib/components/player/VideoPlayer.svelte) | 8 |
+| [settings/+page.svelte](../../src/routes/settings/+page.svelte) | 5 |
+| [sleepTimer.ts](../../src/lib/stores/sleepTimer.ts) / [auth.ts](../../src/lib/stores/auth.ts) / [autoplay.ts](../../src/lib/api/autoplay.ts) | 4 each |
+| [preload.ts](../../src/lib/services/preload.ts) | 3 |
+| [library/[id]](../../src/routes/library/[id]/+page.svelte), [playerEvents.ts](../../src/lib/services/playerEvents.ts), [playbackMode.ts](../../src/lib/stores/playbackMode.ts) | 1–2 each |
+
+These are **not** equivalent violations, and treating them as one number is why
+the rule has been easy to ignore. Three distinct groups:
+
+**(a) Genuine violations — playback control with a facade method that already
+exists.** `playerStop` ×6, `playerPlayTracks` ×4, `playerSeek` ×2,
+`playerPlayAlbumTrack` ×2, `playerNext`, `playerPrevious`, `playerSkipTo`,
+`playerToggleShuffle`, `playerCycleRepeat`, `playerRemoveFromQueue`,
+`playerMoveInQueue`, `playerAddTrackById`, `playerAddTracksByIds`,
+`playerSetSubtitleTrack`, `playerPlayItem`. The facade exposes `stop()`,
+`seek()`, `next()`, `previous()`, `skipTo()`, `toggleShuffle()`,
+`cycleRepeat()`, `removeFromQueue()`, `moveInQueue()`, `addTrackById()`,
+`addTracksByIds()`, `setSubtitleTrack()`, `playTracks()`, `playAlbumTrack()`,
+`playItem()` — every one of these has a facade equivalent that is simply not
+being called. `queue.ts` is the starkest case: it imports `commands` directly
+and re-implements ten methods the facade already provides.
+
+**(b) Playback control with no facade method.** `playerPlayQueue`,
+`playerGetQueue`, `playerGetStatus`, `playerEnterBackgroundAudio`,
+`playerExitBackgroundAudio`, `playerSetSleepTimer`, `playerCancelSleepTimer`,
+`playerPlayNextEpisode`, `playerCancelAutoplayCountdown`. In scope for the
+principle, but currently *impossible* to comply with — the facade has no surface
+for them. A rule that cannot be followed is not being broken so much as it is
+unfinished.
+
+**(c) Not playback control.** `playerConfigureJellyfin` ×3,
+`playerDisableJellyfin`, `playerGet/SetAudioSettings`,
+`playerGet/SetVideoSettings`, `playerGetEqPresets`,
+`playerGet/SetAutoplaySettings`, `playerGet/SetCacheConfig`,
+`playerPreloadUpcoming`. These are configuration and lifecycle calls that happen
+to live under the `player_` command prefix. The principle is about *who is
+authoritative for playback state* — settings CRUD isn't that.
+
+The audit's read: the rule as written is violated 52 times, which makes real
+drift indistinguishable from acceptable usage, and that ambiguity is what lets
+group (a) persist. Note also that the principle **is** well-honoured where it
+matters most — the read side is clean, with UI reading state exclusively from
+the facade's re-exported stores. The write side is what drifted.
+
+## Layer assignment
+
+Frontend-internal refactor. No domain logic moves and nothing new crosses IPC —
+the same Rust commands are called, through one module instead of many.
+
+| Logic / responsibility | Layer | Why it belongs there |
+|------------------------|-------|----------------------|
+| Playback command dispatch (adapter routing: native vs HTML5) | Frontend — `src/lib/player/` **only** | Presentation-layer plumbing, but must be centralised: the facade picks between the native backend and the HTML5 `<video>` adapter. A caller bypassing it silently skips that routing. |
+| Playback *authority* (position, pause, rate, track changes) | **Rust / the player** | Unchanged. The player is authoritative; UI is a consumer. This spec does not touch that direction. |
+| Queue mutation commands | Frontend facade → Rust | Rust owns queue state; the facade is the single call path to it. |
+| Player settings CRUD (EQ, video, autoplay, cache) | Frontend, **outside** the facade | Configuration, not playback control — read/written on a settings page with no adapter routing. Explicitly carved out below. |
+| Backend→frontend event handling | `playerEvents.ts` | Already correct. It is the facade's own plumbing, not a bypassing consumer. |
+
+No Jellyfin taxonomy is involved, so no boundary-leak risk.
+
+## Design
+
+### 1. Narrow the principle to what it actually means
+
+Amend CLAUDE.md and [02-svelte-frontend.md](../architecture/02-svelte-frontend.md):
+
+> **Unified player boundary.** UI controls **playback** — transport, queue
+> mutation, track selection, playback initiation — *only* through
+> `playerController`. Player **configuration** commands (`player_*_settings`,
+> `player_configure_jellyfin`, `player_*_cache_config`, `player_preload_upcoming`)
+> are ordinary IPC and may be called directly from settings surfaces.
+
+This is a clarification, not a relaxation: it makes group (c) explicitly fine so
+that a violation count means something. A rule with 52 nominal violations, most
+of them acceptable, provides no signal.
+
+### 2. Fill the facade gaps (group b)
+
+Add to `playerController`, each a thin pass-through preserving current
+behaviour:
+
+```ts
+playQueue, getQueue, getStatus,
+enterBackgroundAudio, exitBackgroundAudio,
+setSleepTimer, cancelSleepTimer,
+playNextEpisode, cancelAutoplayCountdown,
+```
+
+Do this **first** — group (a) cannot be fully migrated while callers still need
+a direct import for a neighbouring call, and a file that imports `commands` for
+one reason will keep using it for others.
+
+### 3. Migrate group (a)
+
+Mechanical: replace `commands.playerX(...)` with `playerController.x(...)`.
+Highest-value first: `queue.ts` (10 sites, all direct facade equivalents), then
+`player/[id]/+page.svelte`, `VideoPlayer.svelte`, `sleepTimer.ts`,
+`playbackMode.ts`, `library/[id]/+page.svelte`.
+
+Two sites need care rather than substitution:
+
+- **`playerEvents.ts`** (`playerOnPlaybackEnded`, `playerStop` in the error
+  path). This module *is* the facade's event plumbing — the counterpart to
+  `index.ts`, inside the boundary conceptually though not by directory. Treat
+  `src/lib/services/playerEvents.ts` as **inside** the boundary and exempt it,
+  rather than making it call the facade that calls back into it. Record this in
+  the lint config with the reason.
+- **`VideoPlayer.svelte`** — registers its own adapter via `setActiveAdapter`.
+  Its `playerStop`/`playerPlayItem` calls interact with adapter lifecycle, and
+  CLAUDE.md's gotcha ("no lifecycle calls after an `await` in `onMount`") applies.
+  Migrate this file **last and on its own**, so an Android seek regression is
+  bisectable to one commit.
+
+### 4. Add the lint rule (the part that makes it stick)
+
+The audit's finding was that principles with working checks held up and
+principles without them drifted. This principle has no check. Add
+`scripts/check-player-boundary.sh`, wired as `bun run check:player-boundary` and
+into `test-all.sh`:
+
+```sh
+# Playback-control commands that MUST go through the facade.
+CONTROL='player(Play|Pause|Toggle|Stop|Seek|Next|Previous|SkipTo|ToggleShuffle|CycleRepeat|RemoveFromQueue|MoveInQueue|SetVolume|ToggleMute|SetSubtitleTrack|SeekVideo|SwitchAudioTrack|PlayTracks|PlayAlbumTrack|PlayItem|PlayQueue|AddTrackById|AddTracksByIds|GetQueue|GetStatus|EnterBackgroundAudio|ExitBackgroundAudio|SetSleepTimer|CancelSleepTimer|PlayNextEpisode|CancelAutoplayCountdown|OnPlaybackEnded)'
+
+# Inside the boundary: the facade and its event plumbing.
+EXEMPT='^src/lib/player/|^src/lib/services/playerEvents\.ts$'
+```
+
+Flag `commands.$CONTROL` in non-test `src/` files outside `EXEMPT`. Config
+commands are deliberately absent from the list, matching §1 — so the check
+encodes the narrowed rule rather than the aspirational one.
+
+An ESLint `no-restricted-syntax` rule would give better editor feedback, but the
+project has no ESLint config; a shell check matches the existing
+`check:boundary` precedent and adds no dependency.
+
+## Out of scope
+
+- Changing playback *behaviour* — pure refactor.
+- The one-directional state principle (audited clean; UI reads from facade
+  stores only).
+- Moving settings CRUD behind the facade (§1 explicitly carves it out).
+- Introducing ESLint.
+- Refactoring `VideoPlayer.svelte`'s 2079 lines generally, beyond its facade
+  call sites.
+- The `commands.player*` calls **inside** `src/lib/player/` — that is the
+  facade doing its job.
+
+## Acceptance criteria
+
+- [ ] `playerController` exposes the group-(b) methods listed in §2.
+- [ ] `grep -rn "commands\.player" src/ --include='*.ts' --include='*.svelte' | grep -v '^src/lib/player/' | grep -v 'playerEvents\.ts' | grep -v '\.test\.' | grep -v bindings.ts`
+      returns **only** configuration commands per §1 — no transport, queue, or
+      playback-initiation call.
+- [ ] `queue.ts` no longer imports `commands` from bindings.
+- [ ] `bun run check:player-boundary` exists, is wired into `test-all.sh`, and
+      passes.
+- [ ] The check **fails** when a `commands.playerStop()` is added to a non-exempt
+      file — verify explicitly, as with the other gates in this batch.
+- [ ] The check does **not** fail on `commands.playerSetAudioSettings()` in
+      `settings/+page.svelte` (the §1 carve-out works).
+- [ ] CLAUDE.md and `02-svelte-frontend.md` carry the narrowed wording, including
+      the config carve-out and the `playerEvents.ts` exemption with its reason.
+- [ ] **No behavioural change**: audio and video playback, queue reorder,
+      shuffle/repeat, sleep timer, background audio, and autoplay all behave as
+      before on **both Linux and Android**.
+- [ ] Android seek and `onMount` lifecycle still correct after the
+      `VideoPlayer.svelte` migration (the known-fragile path).
+- [ ] `bun run check` and `bun run test` pass.
+- [ ] `bun run check:boundary` passes.
+- [ ] Changed code carries `// TRACES:` comments.
+- [ ] No Rust change, so no `bindings.ts` regeneration.
+
+## Testing
+
+**Frontend** (`bun run test`):
+- Extend the existing facade tests to cover each new group-(b) method: it
+  forwards to the right command with the right arguments, and routes to the
+  active adapter where applicable.
+- `queue.ts` tests: assert calls land on `playerController`, not `commands`. Mock
+  the facade — a test that mocks `commands` would pass either way and guard
+  nothing.
+- Keep `tauriIntegration.test.ts` and the other IPC param-naming tests green;
+  they cover the camelCase rule this refactor must not disturb.
+
+**Manual** (no automated coverage for these paths):
+- Linux: play/pause/seek/next/prev, queue reorder, shuffle, repeat, sleep timer,
+  transcoded video (HLS), background audio enter/exit.
+- Android: the same, plus lockscreen/MediaSession controls, and **seek after
+  entering the player** — the specific regression CLAUDE.md warns about.
+
+Because this is a pure refactor, the strongest signal is that no test *changes
+expectation*. A test needing its assertions rewritten means behaviour moved —
+investigate rather than update it.
+
+## TRACES
+
+Allocate in `requirements.md`:
+
+- **DR-095** — "UI playback control is routed exclusively through the
+  `playerController` facade (`src/lib/player/`), with `playerEvents.ts` inside
+  the boundary as its event plumbing and player *configuration* commands
+  explicitly outside it; enforced by `scripts/check-player-boundary.sh`."
+  Category: Player. Traces to UR-005. Status: Done on merge.
+
+```typescript
+// src/lib/player/index.ts
+// TRACES: UR-005 | DR-095
+```
+
+New facade tests take `@req-test: UT-089` onward (next free UT is **UT-089**;
+coordinate if landing alongside the sibling specs, which draw from the same
+pool).
+
+## Notes for the implementer
+
+- A parallel Claude session may be active in this repo — `git diff` before
+  "repairing" unexpected changes (CLAUDE.md §Gotchas).
+- **Order matters**: §2 (fill gaps) → §3 (migrate, `VideoPlayer.svelte` last and
+  alone) → §4 (add the check). Adding the check first turns `master` red.
+- 🔴 **`VideoPlayer.svelte`**: no lifecycle calls after an `await` in `onMount` —
+  it flips to HTML5 mode and breaks Android seek. Do not let a mechanical
+  substitution introduce an `await` before a lifecycle call.
+- The facade's `requireHandle()` may throw where a raw `commands` call did not.
+  Check each migrated call site's error handling rather than assuming the
+  try/catch still covers the same cases.
+- `playbackMode.ts` interacts with remote-mode routing (`play_on_session` vs
+  local MPV). Verify remote casting still works after migrating its
+  `playerPlayTracks` call.
+- This spec is deliberately the *lowest* priority of the audit batch: it is the
+  largest diff and the only one carrying real regression risk, while the
+  traceability gate is a few lines and restores a dead safety net.

docs/specs/req-coverage-script-removal.md

@@ -0,0 +1,161 @@
+# Spec: Remove the broken `check-req-coverage.sh`
+
+**Status:** Implemented
+**Requirements:** supports DR-093 (see [traceability-gate-repair.md](traceability-gate-repair.md))
+**UX spec:** n/a — developer tooling.
+**Supersedes / revises:** n/a
+
+## Summary
+
+`scripts/check-req-coverage.sh` is broken, orphaned, and actively misleading: it
+reports `Total Requirements: 1`, zeros in every category, and then prints
+**"✨ All requirements have implementations!"**. Nothing references it — not CI,
+not `package.json`, not the docs. This spec deletes it, with a narrowly-scoped
+alternative (repair it) documented and rejected below.
+
+## Motivation
+
+Running it today produces:
+
+```
+Category Breakdown:
+UR:    0 requirements
+IR:    0 requirements
+DR:    0 requirements
+JA:    0 requirements
+
+Summary:
+Total Requirements:       1
+✅ Fully Implemented:     0 (0%)
+
+✨ All requirements have implementations!
+```
+
+Every number is wrong (the real totals are UR 61, IR 29, DR 89, JA 32), and the
+concluding message is the *opposite* of a warning — a developer running this to
+sanity-check coverage is told everything is fine.
+
+This is worse than having no script. It is a trap, and it sits in `scripts/`
+next to tools that do work, with nothing marking it as dead.
+
+Verification that it is genuinely orphaned:
+
+```console
+$ grep -rn "check-req-coverage" . --include='*.yml' --include='*.json' \
+      --include='*.sh' --include='*.md' | grep -v node_modules
+(no output)
+```
+
+## Layer assignment
+
+Developer tooling only; no application logic and nothing crosses the IPC
+boundary.
+
+| Logic / responsibility | Layer | Why it belongs there |
+|------------------------|-------|----------------------|
+| Requirement-coverage reporting | Build tooling — `extract-traces.ts` | One tool should own coverage analysis. A second, divergent implementation is how the two answers ("1 requirement" vs "211") came to disagree unnoticed. |
+
+## Design
+
+**Delete `scripts/check-req-coverage.sh`.**
+
+Coverage reporting is owned by [scripts/extract-traces.ts](../../scripts/extract-traces.ts),
+which is correct, is what CI runs, and gains a first-class local coverage mode
+in [traceability-gate-repair.md](traceability-gate-repair.md):
+
+```bash
+bun run traces:coverage   # the supported way to check coverage locally
+```
+
+Then check the sibling scripts for the same rot. `scripts/` also contains
+`check-test-coverage.sh` and `find-req-implementations.sh`, neither of which is
+referenced from `package.json`. An unreferenced script is never run and so rots
+silently — that is the actual failure mode being fixed here, and fixing only the
+one instance found by audit leaves the others to be rediscovered later.
+
+### Findings (investigation, 2026-07)
+
+All three scripts turned out to share a **single root cause**, and all three are
+deleted:
+
+| Script | Defect |
+|---|---|
+| `check-req-coverage.sh` | Reads `README.md`, which has held **zero** requirement rows since they moved to `docs/requirements.md` → `total_reqs=1`, every category 0, "✨ All requirements have implementations!" Also greps `src-tauri/` unscoped. |
+| `check-test-coverage.sh` | Greps `src-tauri/` unscoped — including **40 GB** of `target/` build artifacts. Hangs indefinitely; produces no output at all. |
+| `find-req-implementations.sh` | Same unscoped `src-tauri/` grep. Same hang. |
+
+So none of them were subtly wrong — two could never terminate, and the third
+inverted its own conclusion.
+
+They were nonetheless *salvageable*: scoping the greps to `src-tauri/src` and
+repointing at `docs/requirements.md` would be a few lines, and the `@req:` /
+`@req-test:` tags they read are still present in the tree (**146** and **76**
+occurrences).
+
+**Decision: delete all three anyway.** The tags are an undocumented parallel
+convention — `@req:` appears in no doc, and CLAUDE.md describes only `TRACES:`.
+Repairing the scripts would re-establish a second traceability system to keep in
+sync with the first, which is the same two-sources-of-truth condition that let
+"1 requirement" and "211 requirements" coexist unnoticed. `TRACES:` plus the
+repaired coverage engine ([traceability-gate-repair.md](traceability-gate-repair.md))
+already cover this ground.
+
+The existing `@req:` / `@req-test:` comments are left in place: they are
+harmless as prose, several encode genuinely useful test intent, and stripping
+222 comments across the tree is a large diff with no functional gain. They are
+simply no longer read by any tool.
+
+### Alternative considered: repair rather than delete
+
+Rejected. The script's output format duplicates what `traces:markdown` already
+generates, it has no tests, no caller, and no documented purpose distinct from
+`extract-traces.ts`. Repairing it recreates the two-sources-of-truth condition
+that produced the contradiction. If a shell-based coverage check is ever wanted,
+it should shell out to `traces:json` and `jq` rather than re-parse
+`requirements.md` independently.
+
+## Out of scope
+
+- The CI workflow denominators — [traceability-gate-repair.md](traceability-gate-repair.md).
+- Any change to `extract-traces.ts`'s output (that spec owns it).
+- Auditing scripts that *are* referenced from `package.json` — they run
+  regularly and would fail visibly.
+
+## Acceptance criteria
+
+- [ ] `scripts/check-req-coverage.sh` no longer exists.
+- [ ] `grep -rn "check-req-coverage" .` (excluding `node_modules` and this spec)
+      returns nothing — no dangling reference in CI, docs, or `package.json`.
+- [ ] `scripts/check-test-coverage.sh` and `find-req-implementations.sh` have each
+      been run and either wired into `package.json` or deleted; the decision and
+      reason are recorded in `scripts/README.md`. **Outcome: all three deleted —
+      see Findings.**
+- [ ] `scripts/README.md` documents `bun run traces:coverage` as the supported
+      way to check requirement coverage locally.
+- [ ] `bun run test:all` passes (confirms nothing invoked the deleted script).
+- [ ] `bun run check` and `bun run test` pass.
+- [ ] `bun run check:boundary` passes.
+
+## Testing
+
+No unit tests — this is a deletion. Verification is the grep in the acceptance
+criteria plus a green `bun run test:all`, which exercises the script paths that
+actually run.
+
+## TRACES
+
+No new requirement. The deletion is covered by **DR-093**
+([traceability-gate-repair.md](traceability-gate-repair.md)), which establishes
+`extract-traces.ts` as the single owner of coverage reporting. Note the removal
+in that DR's text when both land.
+
+## Notes for the implementer
+
+- A parallel Claude session may be active in this repo — `git diff` before
+  "repairing" unexpected changes (CLAUDE.md §Gotchas).
+- Land this **after** or alongside [traceability-gate-repair.md](traceability-gate-repair.md),
+  so `bun run traces:coverage` exists before the broken script is removed and
+  developers are never left without a coverage command.
+- Check `docs/traceability-ci.md` and `docs/traces-quick-ref.md` for prose
+  references to the deleted script; the grep above covers `.md`, but read the
+  surrounding sentence rather than deleting the line mechanically.

docs/specs/scoped-search-boundary-implementation.md

@@ -0,0 +1,254 @@
+# Spec: Land the scoped-search boundary fix (implementation)
+
+**Status:** Stage 1 Implemented — Stage 2 (result-side grouping) outstanding
+**Requirements:** UR-049, UR-050 | DR-063, DR-066, DR-067 (existing — no new IDs)
+**UX spec:** n/a — zero user-visible change is the point (see Acceptance criteria).
+**Supersedes / revises:** implements [scoped-search-boundary.md](scoped-search-boundary.md),
+which specified this fix but was never built. That spec remains the **design
+authority**; this one is the delivery plan and status correction.
+
+## Summary
+
+[scoped-search-boundary.md](scoped-search-boundary.md) diagnosed a domain-taxonomy
+leak, specified the fix in full detail, and became the justification for the
+project's boundary rule in CLAUDE.md, the `check:boundary` tripwire, and the
+spec-review checklist. **The fix was never implemented.** The leak it describes
+is still live in `main`. This spec exists to close that gap and to correct the
+record — the codebase currently enforces a rule against a violation it still
+contains.
+
+## Motivation
+
+The mapping the rule forbids is present and in use:
+
+```ts
+// src/lib/utils/searchScope.ts:29-32
+const SCOPE_ITEM_TYPES: Record<Exclude<SearchScope, "all">, string[]> = {
+  music: ["MusicAlbum", "MusicArtist", "Audio", "Playlist"],
+  movies: ["Movie"],
+  tv: ["Series", "Episode"],
+};
+```
+
+This is not dead code. [library.ts:262](../../src/lib/stores/library.ts#L262)
+calls `scopeItemTypes(scope)` and puts the result straight into
+`options.includeItemTypes`. Meanwhile there is **no `SearchScope` anywhere in
+`src-tauri/`**:
+
+```console
+$ grep -rn "SearchScope" src-tauri/src --include='*.rs'
+(no output)
+```
+
+Three things make this the highest-value item found in the design-principles
+audit:
+
+1. **The rule's own founding incident is unremediated.** CLAUDE.md cites this
+   spec as "the incident this rule came from." A rule whose originating
+   violation is still shipping is not credible.
+2. **The tripwire cannot see it.** `bun run check:boundary` passes — it greps for
+   a multi-type array literal *at the query site*, and this one is assigned to a
+   named const and dereferenced elsewhere. Broadening the tripwire is specified
+   separately in [boundary-tripwire-hardening.md](boundary-tripwire-hardening.md);
+   note that hardening it **without** landing this fix would turn `master` red.
+3. **The spec's own acceptance criterion fails today.** "Adding a hypothetical
+   new type to a scope requires editing only Rust" — adding a type to the Music
+   scope right now requires editing `searchScope.ts`.
+
+## Layer assignment
+
+Unchanged from [scoped-search-boundary.md](scoped-search-boundary.md) §Design;
+restated so this spec is reviewable on its own.
+
+| Logic / responsibility | Layer | Why it belongs there |
+|------------------------|-------|----------------------|
+| Scope → Jellyfin item types (`music` → `MusicAlbum`, `MusicArtist`, `Audio`, `Playlist`) | **Rust** | Domain vocabulary. Changes if Jellyfin adds/renames an item type — the litmus test's "yes" case. This is the leak being fixed. |
+| Result item → search group bucketing | **Rust** | Same taxonomy, result side. Classifying a `MediaItem` as a Song vs Album is Jellyfin vocabulary, not layout. |
+| `All` sends no filter at all (≠ union of enumerated types) | **Rust** | A query-shaping rule with a correctness consequence (Person/folder results would be silently dropped). Belongs with the expansion it qualifies. |
+| Group display order, labels, reordering, persistence | Frontend | Pure presentation — changes only if the UI is redesigned. Explicitly retained frontend-side. |
+| `resolveSearchScope(pathname)` — route → initial scope | Frontend | Routing/navigation, no Jellyfin vocabulary. Stays exactly as-is. |
+| Chip labels (`SCOPE_LABELS`), scope order (`SEARCH_SCOPES`) | Frontend | Display strings over an opaque enum. |
+| `GROUP_SCOPE` (which group belongs to which scope) | **Delete** | Borderline taxonomy, made redundant: once Rust filters by scope, out-of-scope groups arrive empty and drop via the empty-omit rule. Borderline defaults to Rust; here it defaults to *gone*. |
+
+The `SearchScope` and `SearchGroupId` **types** come to the frontend from
+generated `bindings.ts`. Naming an opaque enum variant is not taxonomy; knowing
+what item types it expands to is.
+
+## Design
+
+**Follow [scoped-search-boundary.md](scoped-search-boundary.md) §Design as
+written** — `SearchScope` enum + `item_types()` in `repository/types.rs`,
+`SearchOptions.scope`, `SearchGroupId`/`SearchGroup`/`GroupedSearchResult`,
+scope-wins precedence, `All` → `None` → no filter. It is not restated here;
+duplicating it would create two drifting copies of the same design.
+
+This spec adds only the delivery sequencing that the original left implicit.
+
+### Staging: land it in two reviewable pieces
+
+The original bundles the query side and the result side into one change. That is
+a large diff touching Rust types, `bindings.ts`, the store, and a component, with
+the `search-event` dual-payload hazard in the middle. Split it:
+
+**Stage 1 — query side (closes the leak).**
+`SearchScope` enum, `SearchOptions.scope`, command resolves scope →
+`include_item_types` in Rust, `library.ts` sends `{ scope }`, delete
+`SCOPE_ITEM_TYPES` and `scopeItemTypes()`. Result grouping stays as it is.
+
+After Stage 1 the actual boundary violation is gone and
+[boundary-tripwire-hardening.md](boundary-tripwire-hardening.md) can land safely.
+
+**Stage 2 — result side.** `SearchGroupId`/`SearchGroup`/`GroupedSearchResult`,
+Rust bucketing, both payloads converted, `composeSearchGroups()` shrunk,
+`GROUP_ITEM_TYPES`/`groupItemTypes()`/`GROUP_SCOPE` deleted.
+
+Both stages are required for the original spec's acceptance criteria to pass;
+Stage 1 alone leaves `GROUP_ITEM_TYPES` in the frontend. **Stage 1 is not a
+stopping point** — it is a review boundary. Do not mark the parent spec
+Implemented until Stage 2 lands.
+
+### Stage 1 — delivered (July 2026)
+
+- `SearchScope` enum + `item_types()` in [repository/types.rs](../../src-tauri/src/repository/types.rs);
+  `All` → `None` → no filter.
+- `SearchOptions.scope` with `resolve_scope()`; scope wins over
+  `include_item_types`, which stays for the non-search `get_items` callers.
+- `repository_search` resolves the scope **once, before** the cache/server split,
+  so both phases filter identically.
+- `SCOPE_ITEM_TYPES` and `scopeItemTypes()` deleted; `searchScope.ts` now
+  re-exports `SearchScope` from the generated bindings instead of a hand-written
+  union.
+- [library.ts](../../src/lib/stores/library.ts) sends `{ scope }`.
+- 8 Rust tests (`search_scope_tests`); the frontend suite now asserts the
+  *opaque scope* is sent rather than an item-type list.
+
+Verified: adding `"AudioBook"` to the Music scope changed **zero** files under
+`src/` — the criterion that failed before this work.
+
+**Stage 2 remains open**: `GROUP_ITEM_TYPES` / `groupItemTypes()` (result-side
+bucketing, single-type-per-group) are still in `searchScope.ts`, and both search
+payloads still carry a flat `MediaItem[]` rather than `GroupedSearchResult`.
+
+### 🔴 The `search-event` dual payload (Stage 2)
+
+The original flags this as "the single largest part of the change and the
+easiest to half-do." Restating because it is the one thing that silently breaks:
+search resolves **twice** — the command returns instant cache results, then the
+merged cache+server union arrives via `search-event`. Both payloads must carry
+`GroupedSearchResult`. Convert one and the UI flickers between shapes as server
+results land.
+
+Write the failing test for the *event* payload first — the command return is the
+obvious half, the event is the half that gets forgotten.
+
+### Note on `SearchOptions.scope` and specta
+
+`SearchOptions` is already `#[serde(rename_all = "camelCase")]` with
+`skip_serializing_if = "Option::is_none"`. Add `scope: Option<SearchScope>`
+following that pattern so `All`/absent omits the key. Regenerate `bindings.ts`
+— `SearchOptions` there is currently
+`{ limit?, includeItemTypes?, searchTerm? }` and must gain `scope?`. Never
+hand-edit it.
+
+## Out of scope
+
+- Redesigning anything in [scoped-search-boundary.md](scoped-search-boundary.md).
+  If implementation shows the design wrong, revise **that** spec, don't fork it.
+- Online/offline `include_item_types` **filtering** — already correct; only the
+  source of the type list moves.
+- Ranking within or across groups (DR-090 territory).
+- Chip UX, scope persistence, group-order persistence — unchanged.
+- The two lesser type-set sites in `DownloadedBrowse.svelte` and
+  `GenericMediaListPage.svelte`, handled in
+  [boundary-tripwire-hardening.md](boundary-tripwire-hardening.md).
+- Broadening the tripwire itself — same sibling spec.
+
+## Acceptance criteria
+
+Inherits every criterion from [scoped-search-boundary.md](scoped-search-boundary.md)
+§Acceptance criteria. Additionally:
+
+- [ ] `grep -rn "SearchScope" src-tauri/src --include='*.rs'` returns matches —
+      the enum exists in Rust (it does not today).
+- [ ] `grep -n "SCOPE_ITEM_TYPES\|scopeItemTypes\|GROUP_ITEM_TYPES\|groupItemTypes" src/lib/utils/searchScope.ts`
+      returns nothing.
+- [ ] `grep -rn "scopeItemTypes" src/` returns nothing — including the
+      `library.ts` import and call site.
+- [ ] `SearchOptions` in `bindings.ts` includes `scope`; regenerated, not
+      hand-edited.
+- [ ] **Behaviour is byte-identical for the user**: same scoping, same groups,
+      same order, same empty-group omission, offline included. This spec is a
+      pure refactor — any visible change is a defect.
+- [ ] `All` scope sends no `includeItemTypes` (asserted in a Rust test, not by
+      inspection).
+- [ ] Adding a type to the Music scope requires editing **only** Rust —
+      demonstrate by making the edit and confirming no `src/` file changes.
+- [ ] `scoped-search-boundary.md` status flips to **Implemented**, and
+      `scoped-search.md`'s "frontend only, no Rust changes" framing gets a
+      banner pointing at the corrected design.
+- [ ] `bun run check` and `bun run test` pass.
+- [ ] `cargo fmt` clean, `cargo clippy` clean, `bun run test:rust` passes.
+- [ ] `bun run check:boundary` passes.
+- [ ] Changed code carries `// TRACES:` comments (IDs below).
+
+## Testing
+
+Follow [scoped-search-boundary.md](scoped-search-boundary.md) §Testing. Emphases:
+
+**Rust** (`cargo test`):
+- `SearchScope::item_types()` per scope; `All` → `None`.
+- Scope resolution happens **before** the online/offline split, so both paths
+  get the same filter — a regression here is invisible until someone searches
+  offline.
+- `scope` set + `include_item_types` set → scope wins (the documented
+  precedence; assert it rather than trusting the doc).
+- Stage 2: mixed `Vec<MediaItem>` buckets correctly; unknown types dropped;
+  canonical group order; **the `search-event` payload is the grouped shape**.
+
+**Frontend** (`bun run test`):
+- `resolveSearchScope()` tests in `searchScope.test.ts` must pass **unchanged** —
+  they cover the part that is not moving, and are the regression net proving the
+  refactor didn't disturb routing.
+- `library.ts` sends `{ scope }` and never `includeItemTypes` for search.
+- `composeSearchGroups()` over fixture `SearchGroup[]` with no `.type`
+  inspection in the implementation.
+
+**Offline parity:** run a scoped search with the server unreachable and confirm
+identical grouping. The offline repository path honours `include_item_types`
+independently, and this is the case most likely to be missed.
+
+## TRACES
+
+No new requirement IDs — this implements existing ones. Retag as the code moves:
+
+```rust
+// src-tauri/src/repository/types.rs
+/// TRACES: UR-049 | DR-063
+pub enum SearchScope { … }
+```
+
+```typescript
+// src/lib/utils/searchScope.ts — keep the file header; it retains
+// resolveSearchScope + group-order presentation logic.
+// TRACES: UR-049, UR-050 | DR-063, DR-066, DR-067
+```
+
+Update DR-063's text in `requirements.md` to state that scope expansion is owned
+by Rust, so the requirement stops describing the leaked design. New Rust tests
+take `@req-test: UT-089` onward (next free UT is **UT-089**).
+
+## Notes for the implementer
+
+- A parallel Claude session may be active in this repo — `git diff` before
+  "repairing" unexpected changes (CLAUDE.md §Gotchas).
+- **Read [scoped-search-boundary.md](scoped-search-boundary.md) first.** This
+  spec is deliberately thin on design; that one is the authority.
+- Sequence with the sibling specs: **Stage 1 here → then
+  [boundary-tripwire-hardening.md](boundary-tripwire-hardening.md)**. Hardening
+  the tripwire first turns `master` red on a known-unfixed violation.
+- `git log --oneline -- docs/specs/scoped-search-boundary.md` is worth a look
+  before starting — understanding why the fix stalled may surface a constraint
+  the spec didn't record.
+- The user-visible-change count for this spec is zero. If QA reports a
+  difference in search results, that is a bug in the refactor, not an
+  improvement.

docs/specs/scoped-search.md

@@ -8,8 +8,14 @@
 > is being moved into Rust. The **user-facing behaviour and UX in this spec are
 > unchanged**; only where the scope→item-type mapping and result bucketing live
 > changes. Read the boundary spec before touching search code.
+>
+> **Progress:** the scope→item-type mapping now lives in Rust
+> (`SearchScope::item_types()`); the frontend sends an opaque scope. Result-side
+> bucketing (`GROUP_ITEM_TYPES`) is still frontend-side — see
+> [scoped-search-boundary-implementation.md](scoped-search-boundary-implementation.md)
+> §Stage 2.
 
-**Status:** Implemented (boundary revision pending — see banner above)
+**Status:** Implemented (boundary revision: query side done, result side pending)
 **Scope:** Frontend only. No Rust changes required. *(Revised — see banner.)*
 **Requirements:** UR-049 → DR-063, DR-064, DR-065; UR-050 → DR-066, DR-067
 (see [requirements.md](../requirements.md)).

docs/specs/traceability-gate-repair.md

@@ -0,0 +1,238 @@
+# Spec: Repair the traceability coverage gate
+
+**Status:** Implemented
+**Requirements:** DR-093 → supports the traceability practice described in CLAUDE.md
+**UX spec:** n/a — developer tooling, no user-facing surface.
+**Supersedes / revises:** n/a
+
+## Summary
+
+The CI traceability gate has been passing unconditionally for an unknown length
+of time because it divides traced-requirement counts by **hardcoded denominators
+that no longer match [requirements.md](../requirements.md)**. It currently
+reports **158% overall coverage** (and `JA 24 / 3 = 800%`), so the 50% threshold
+is mathematically unreachable and the job cannot fail. This spec makes the gate
+derive its denominators from `requirements.md` at run time, so it reports the
+real number (**85%** today) and can actually fail again.
+
+## Motivation
+
+`.gitea/workflows/traceability-check.yml` hardcodes `UR/39, IR/24, DR/48, JA/3`
+and `TOTAL_REQS=114`. The real counts are **UR 61, IR 29, DR 89, JA 32 — 211
+total**. Requirements were added over time; the divisors were never updated.
+
+The consequence is not a cosmetic reporting bug. The gate is the *only*
+automated defence for the traceability practice, and it is dead:
+
+```
+CI today:  181 / 114 = 158%  → threshold 50% can never trip
+Reality:   181 / 211 =  85%  → healthy, but unguarded
+```
+
+Coverage could collapse to 30% and CI would still print a green
+"✅ Coverage is acceptable". An audit of the design principles found that every
+principle with a *working* automated check is in good shape, and the ones that
+drifted are exactly the ones whose checks were broken or too narrow — this is
+the clearest instance.
+
+A second, related defect is handled in a sibling spec: `scripts/check-req-coverage.sh`
+is separately broken and orphaned (see
+[req-coverage-script-removal.md](req-coverage-script-removal.md)).
+
+## Layer assignment
+
+This spec touches only CI/build tooling — no application logic crosses the
+Rust/Svelte boundary. The table is filled in for completeness.
+
+| Logic / responsibility | Layer | Why it belongs there |
+|------------------------|-------|----------------------|
+| Counting requirement IDs defined in `requirements.md` | Build tooling (`scripts/`) | Neither runtime layer; it is repo metadata analysis. Belongs beside `extract-traces.ts`, not in the workflow YAML, so it is runnable and testable locally. |
+| Counting *traced* requirement IDs | Build tooling — existing `extract-traces.ts` | Already implemented and correct; this spec consumes it rather than duplicating it. |
+| Threshold policy (the 50% number) | CI workflow | Deployment policy, not analysis. Keeping it in YAML lets it be tuned without touching the script. |
+
+No frontend or Rust logic is added, so no taxonomy leak is possible.
+
+## Design
+
+### 1. Denominators come from `requirements.md`, not literals
+
+`requirements.md` defines requirements in markdown tables with a stable leading
+cell, e.g.:
+
+```
+| DR-001 | Player state machine (idle, loading, …) | Player | UR-005 | Done |
+| UR-002 | Access media when online or offline | High | Done |
+```
+
+Extend [scripts/extract-traces.ts](../../scripts/extract-traces.ts) to also emit
+the *defined* counts, so one tool owns both sides of the fraction and CI does no
+arithmetic on stale literals. Add a `defined` key to the JSON report:
+
+```jsonc
+{
+  "byType":   { "UR": [...], "IR": [...], "DR": [...], "JA": [...] },  // traced (existing)
+  "defined":  { "UR": 61, "IR": 29, "DR": 89, "JA": 32 },              // NEW
+  "coverage": { "covered": 181, "total": 211, "percent": 85 },         // NEW
+  "requirements": { ... },                                             // existing
+  "totalTraces": 318, "totalFiles": …, "timestamp": "…"                // existing
+}
+```
+
+Parsing rule for a *defined* requirement: a line in `docs/requirements.md`
+matching `^\|\s*(UR|IR|DR|JA)-\d{3}\s*\|` — the ID must be the table's first
+cell. This deliberately does **not** count IDs mentioned in the `Traces To`
+column or in prose, which is why a naive `grep -o` over the whole file
+overcounts.
+
+`defined` counts IDs that exist in the spec; `byType` counts IDs that appear in
+a `TRACES:` comment somewhere in the source. Coverage is
+`|byType ∩ defined| / |defined|`.
+
+> **Intersection, not raw length.** A `TRACES:` comment naming an ID that
+> `requirements.md` does not define (a typo, or a requirement later deleted)
+> must **not** inflate the numerator — that is how a ratio exceeds 100% in the
+> first place. Such IDs are reported separately as `orphaned` so they get fixed
+> rather than silently counted or silently dropped.
+
+```jsonc
+"orphaned": ["DR-097"]   // traced in code but not defined in requirements.md
+```
+
+### 2. The workflow consumes the computed number
+
+Replace the arithmetic in `.gitea/workflows/traceability-check.yml` (lines
+46–76) with reads of the precomputed fields:
+
+```sh
+COVERAGE=$(jq '.coverage.percent' traces-report.json)
+COVERED=$(jq '.coverage.covered' traces-report.json)
+TOTAL_REQS=$(jq '.coverage.total'   traces-report.json)
+
+for T in UR IR DR JA; do
+  TRACED=$(jq --arg t "$T" '.byType[$t] | length' traces-report.json)
+  DEFINED=$(jq --arg t "$T" '.defined[$t]'        traces-report.json)
+  echo "   $T: $TRACED / $DEFINED"
+done
+
+MIN_THRESHOLD=50
+[ "$COVERAGE" -lt "$MIN_THRESHOLD" ] && { echo "❌ …"; exit 1; }
+```
+
+No hardcoded denominator survives anywhere in the workflow.
+
+### 3. A self-check so this cannot silently rot again
+
+The root cause was a number that drifted with nothing watching it. Add a
+guard that fails the job on an arithmetically impossible result:
+
+```sh
+if [ "$COVERAGE" -gt 100 ]; then
+  echo "❌ Coverage > 100% — the gate is miscomputing; orphaned IDs: $(jq -c '.orphaned' traces-report.json)"
+  exit 1
+fi
+```
+
+A >100% reading is now a hard failure rather than a green tick.
+
+### 4. Local parity
+
+Add a script so the gate is runnable outside CI:
+
+```jsonc
+"traces:coverage": "bun run scripts/extract-traces.ts --format coverage"
+```
+
+Prints the same table CI prints and exits non-zero below threshold.
+
+### Threshold
+
+Keep `MIN_THRESHOLD=50` in this spec. Real coverage is 85%, so raising the bar
+is tempting, but doing it in the same change that repairs the gate conflates
+"restore the safety net" with "tighten the policy" — if the build then fails, it
+is ambiguous which change caused it. Ratcheting is deliberately deferred to
+follow-up work once the honest number has been observed on `master` for a few
+builds.
+
+## Out of scope
+
+- Raising `MIN_THRESHOLD` above 50 (see above).
+- Fixing/removing `scripts/check-req-coverage.sh` — [req-coverage-script-removal.md](req-coverage-script-removal.md).
+- Adding TRACES comments to raise the actual coverage number.
+- Changing the `TRACES:` comment format or the extractor's parsing of it.
+- The PR "modified files missing TRACES" step (lines 78–126), which is advisory
+  by design and stays advisory.
+
+## Acceptance criteria
+
+- [ ] `bun run traces:json` emits `defined`, `coverage`, and `orphaned` keys.
+- [ ] `coverage.total` equals the count of requirement IDs defined in
+      `requirements.md` (**211** at time of writing), not a literal.
+- [ ] `coverage.percent` reports **85** (±1 for rounding) on the current tree —
+      i.e. the honest number, not 158.
+- [ ] No hardcoded requirement denominator (`39`, `24`, `48`, `3`, `114`) remains
+      in `.gitea/workflows/traceability-check.yml`. Verify:
+      `grep -nE '/ *(39|24|48|3|114)\b' .gitea/workflows/traceability-check.yml`
+      returns nothing.
+- [ ] Adding a new requirement row to `requirements.md` **lowers** reported
+      coverage until it is traced (proves the denominator is live).
+- [ ] A `TRACES:` comment naming an undefined ID appears in `orphaned` and does
+      **not** raise `coverage.percent`.
+- [ ] The job fails if coverage is forced below 50% (test by temporarily raising
+      `MIN_THRESHOLD` to 99 locally) — proving the gate can fail again.
+- [ ] The job fails if coverage computes >100%.
+- [ ] `bun run check` and `bun run test` pass.
+- [ ] `bun run check:boundary` passes.
+- [ ] New requirement-implementing code carries `// TRACES:` comments.
+- [ ] No Rust types changed, so no `bindings.ts` regeneration needed.
+
+## Testing
+
+`extract-traces.ts` currently has no test coverage. Add
+`scripts/extract-traces.test.ts` (vitest) over fixture strings rather than the
+live `requirements.md`, so the tests do not change meaning as requirements are
+added:
+
+- **UT:** counts a well-formed table row as a defined requirement.
+- **UT:** does **not** count an ID appearing only in the `Traces To` column or
+  in prose — the specific overcounting bug this parse rule avoids.
+- **UT:** coverage is the intersection — a traced-but-undefined ID lands in
+  `orphaned` and does not inflate the numerator.
+- **UT:** coverage of an empty trace set is 0%, not a divide-by-zero.
+- **UT:** all-traced fixture reports exactly 100%, never above.
+
+CI behaviour is verified by the acceptance criteria above (the forced-failure
+check is the important one — a gate nobody has watched fail is not known to
+work).
+
+## TRACES
+
+Allocate in `requirements.md`:
+
+- **DR-093** — "Traceability coverage gate derives requirement denominators from
+  `requirements.md` at run time (not hardcoded literals), computes coverage as
+  the intersection of traced and defined IDs, reports IDs traced but undefined
+  as orphaned, and fails on an impossible >100% result." Category: Tooling.
+  Status: Done on merge.
+
+Tag:
+
+```typescript
+// scripts/extract-traces.ts
+// TRACES: | DR-093
+```
+
+Tests carry `@req-test: UT-089 …` onward (next free UT is **UT-089**).
+
+## Notes for the implementer
+
+- A parallel Claude session may be active in this repo — run `git diff` before
+  "repairing" unexpected changes (CLAUDE.md §Gotchas).
+- **Do not add tooling to the CI image for this.** `jq` and `bun` are already in
+  `jellytau-builder`; this spec needs nothing else. Installing a system package
+  in a workflow step violates the hard CI rule in CLAUDE.md.
+- Keep `traces:json`'s existing keys intact — `release-notes.ts` and
+  `traces:markdown` consume the same report, and the CI workflow uploads it as
+  an artifact. This is an additive change.
+- The `head -50 docs/traceability.md` and artifact-upload steps are unaffected.
+- Expect the first green build after this change to print a *lower* number than
+  before (85% vs 158%). That is the fix working, not a regression.

docs/specs/windows-native-audio-backend.md

@@ -0,0 +1,209 @@
+# Spec: Windows native audio backend
+
+**Status:** Proposed
+**Requirements:** UR-003, UR-027, UR-032, UR-033 → DR-030, DR-035, DR-036; new IR-030
+**UX spec:** n/a — Settings › Audio already renders the controls
+**Supersedes / revises:** acts on the "audio can unify, video cannot" conclusion in [playback-backend-unification.md](playback-backend-unification.md)
+
+## Summary
+
+Give Windows a real native audio backend instead of the current webview
+`<audio>` shim. Windows is the only platform where audio playback has no decoder
+of its own: `WebviewAudioBackend` hands a URL to a frontend `<audio>` element and
+relays transport commands. It cannot set volume, cannot apply any audio setting,
+and reports state only via DOM events.
+
+Audio needs no rendering surface, so **none of the webview-compositing problems
+that block unified video apply here.** This is the cleanest available win.
+
+## Motivation
+
+`WebviewAudioBackend` was a deliberate stopgap ("audio-only playback for
+platforms without a native audio backend"), and it works — but it has a hard
+functional gap. From `webview_audio_backend.rs`:
+
+```rust
+fn set_volume(&mut self, volume: f32) -> Result<(), PlayerError> {
+    // ...stores locally only; there is no ControlCommand action for volume
+}
+```
+
+So volume changes never reach the element; the frontend has to observe the player
+store and apply volume itself. `set_audio_settings` likewise stores values that
+nothing consumes — EQ, normalization, and gapless are all inert on Windows.
+
+Meanwhile the backend-unification investigation established that a native *audio*
+engine is unproblematic on Windows specifically: `tauri-plugin-libmpv` lists
+Windows as its **fully tested** platform (in contrast to Linux, where embedding
+is broken — but that is a *video surface* problem, which audio does not have).
+
+## Layer assignment
+
+| Logic / responsibility | Layer | Why it belongs there |
+|------------------------|-------|----------------------|
+| Decoding and playing the audio stream | Rust | Playback is domain logic; every other platform already decodes in Rust or a native player. The webview shim is the anomaly. |
+| Applying `AudioSettings` (EQ/normalize/gapless) | Rust | Same `AudioSettings` contract as MPV/ExoPlayer; band layout and presets stay canonical in `settings.rs`. |
+| Position/state reporting | Rust | Restores the project's core principle — the player is the authoritative source of state. Today Windows inverts this: the DOM element is authoritative and Rust mirrors it. |
+| Volume | Rust | Currently broken precisely because it is split across the boundary. |
+| Rendering the player UI | Frontend | Unchanged. |
+
+The strongest argument for this change is the third row. CLAUDE.md states
+playback state is one-directional with the player authoritative; on Windows that
+is currently false, and the `player_report_*` round-trip exists to paper over it.
+
+## Design
+
+### Engine choice
+
+Two viable options; **libmpv is recommended** for consistency with the Linux
+audio backend.
+
+| | libmpv | GStreamer |
+|---|---|---|
+| Windows status | ✅ `tauri-plugin-libmpv` reports fully tested | ✅ works, but… |
+| Rust bindings | `libmpv2` 6.0.0, active | `gstreamer-rs` 0.25.x, excellent |
+| Cross-MSVC from Linux | ⚠️ needs prebuilt DLL + import lib | ❌ `gstreamer-sys` uses pkg-config, fights `cargo-xwin` |
+| Code reuse | ✅ `MpvBackend` logic is directly reusable | ❌ a second engine to learn |
+| Crossfade capable | ❌ single-stream chain | ✅ `audiomixer` |
+
+libmpv wins on reuse: `MpvBackend`'s `set_audio_settings` — the `af` lavfi graph
+built by `build_af_filter`, `eq_filter_entries`, `normalize_filter_entry` — is
+platform-independent and would apply unchanged.
+
+The one reason to prefer GStreamer is crossfade (UR-031), which mpv structurally
+cannot do. If crossfade becomes a priority, revisit; it would then argue for
+GStreamer on *both* Linux and Windows, which is a much larger change.
+
+### Structure
+
+Rename the cfg gate so `MpvBackend` is no longer Linux-only:
+
+```rust
+// src-tauri/src/player/mod.rs
+#[cfg(any(target_os = "linux", target_os = "windows"))]
+pub mod mpv_backend;
+```
+
+`MpvBackend::new` needs one platform-specific branch: `detect_audio_system()`
+currently probes `pactl`/`pw-cli`/`/proc/asound/cards` to pick an `ao`. On
+Windows the equivalent is `wasapi` (mpv's default), so the detection is a
+`#[cfg]` returning `"wasapi"` — no probing needed.
+
+Everything else — the event loop, the 250ms position thread, the seek-suppression
+window, the `af` filter graph — is unchanged.
+
+`WebviewAudioBackend` stays for other targets (macOS and anything else hitting
+the `not(any(...))` arm) and as the fallback if libmpv fails to initialize. The
+existing `emit_backend_init_failed` path already handles that gracefully.
+
+### Build
+
+`libmpv2-sys` is well-suited to cross-compilation: no pkg-config, vendored
+headers, pregenerated bindings (no libclang). It emits `cargo:rustc-link-lib=mpv`
+unconditionally, so the build must supply a linkable import library for
+`x86_64-pc-windows-msvc`.
+
+Keep the `build_libmpv` feature **off** — its Unix path shells out to mpv-build
+and explicitly rejects cross-compilation.
+
+🔴 Per CLAUDE.md, the prebuilt libmpv **must be added to the builder image**
+(`Dockerfile.builder` → rebuild + push via `scripts/build-builder-image.sh`), not
+installed at CI job time. `libmpv-2.dll` must also be bundled into the NSIS
+installer via `tauri.conf.json`'s resources.
+
+### Verified build mechanics
+
+The cross-compile path was tested hands-on from Linux (July 2026), not inferred:
+
+- Neither shinchiro nor zhongfly ships an `mpv.def` or MSVC `mpv.lib` — only a
+  MinGW `libmpv.dll.a`. (Several online sources claim otherwise; they are wrong.)
+- An MSVC-style import lib can be generated locally with LLVM tools only:
+  `llvm-readobj --coff-exports libmpv-2.dll` → synthesize `mpv.def` →
+  `llvm-dlltool -m i386:x86-64 -d mpv.def -l mpv.lib`. `llvm-lib /def:` produces a
+  byte-identical result.
+- A real `lld-link` link against that import lib **succeeds**, and the resulting
+  import table resolves `mpv_client_api_version` from `libmpv-2.dll`. `lld-link`
+  is the linker `cargo-xwin` uses, so this is the load-bearing step.
+- Linking directly against the shipped MinGW `libmpv.dll.a` **also** succeeds, so
+  def-generation may be skippable — but that relies on lld's GNU-archive
+  tolerance rather than a documented contract. Keep `llvm-dlltool` as the
+  fallback.
+- MinGW origin is not an ABI problem: libmpv exports a pure C ABI, and the x86-64
+  Windows calling convention is platform-defined. The upstream note that MSVC
+  cannot *build* mpv is frequently misread as "MSVC cannot *link* libmpv" — that
+  is not what it says.
+- 🔴 Never free/realloc across the DLL boundary — use `mpv_free`.
+
+Build wiring is ordinary: `cargo:rustc-link-lib=dylib=mpv` plus
+`cargo:rustc-link-search`. Nothing about libmpv conflicts with `cargo-xwin`.
+
+### Size and shipping
+
+Measured uncompressed: **93 MiB** (zhongfly `mpv-dev-lgpl-x86_64`) vs **112 MiB**
+(shinchiro, full GPL build); ~26–30 MB compressed in the `.7z`.
+
+**Ship the zhongfly LGPL build** — smaller, and there is no reason to pull the
+GPL variant in for an audio-only use.
+
+Import-table inspection confirms **no companion DLLs are needed**: every
+dependency is a system DLL (`KERNEL32`, `USER32`, `d2d1`, `DWrite`, `OPENGL32`,
+`vulkan-1`, UCRT `api-ms-win-*`). One file to bundle.
+
+93 MiB is still substantial against a Tauri app's usual few MB. Since we use mpv
+audio-only, investigate whether a pruned build (no video decoders, no libplacebo)
+is worth producing for the builder image — but treat that as an optimization,
+not a blocker.
+
+## Out of scope
+
+- Windows *video*. Stays in WebView2 + hls.js — it works and has ABR.
+- Crossfade (UR-031/DR-034) — not implemented anywhere; needs its own spec.
+- Replacing `WebviewAudioBackend` for macOS.
+- MPRIS/SMTC media-key integration — worth a follow-up, not this spec.
+
+## Acceptance criteria
+
+- [ ] Windows build produces a `MpvBackend`-backed player; `backend-init-failed` is emitted (not a crash) if libmpv is unavailable.
+- [ ] Volume control works from the UI — the current hard gap.
+- [ ] EQ, normalization, and gapless audibly take effect on Windows.
+- [ ] Position/state originate in Rust; the `<audio>` element is no longer in the audio path.
+- [ ] Seek, next/previous, and queue advance work; sleep timer stops playback.
+- [ ] `libmpv-2.dll` ships in the NSIS installer and the app runs on a clean Windows VM with no mpv installed.
+- [ ] Builder image carries the Windows libmpv artefacts; **no toolchain install added to any CI step**.
+- [ ] `bun run check`, `bun run test`, `bun run check:boundary` pass.
+- [ ] `cargo fmt` clean, `cargo clippy` clean, `bun run test:rust` passes.
+- [ ] New requirement-implementing code carries `// TRACES:` comments.
+
+## Testing
+
+**Rust**: the existing `mpv_backend_test.rs` and the `build_af_filter` /
+`normalize_filter_entry` / `eq_filter_entries` unit tests already cover the
+filter-graph logic and are platform-independent — they should pass unchanged
+under a Windows `cargo check`/test. Add a test asserting `detect_audio_system()`
+returns `wasapi` under `cfg(windows)`.
+
+**Manual, on Windows**: volume, EQ preset change, normalization toggle, gapless
+between two tracks, seek, queue advance, sleep timer. Then the packaging test —
+install the NSIS output on a clean VM and confirm it launches and plays.
+
+Per CLAUDE.md, the volume gap is a *bug fix*: write a failing test for
+"`set_volume` reaches the backend" before implementing.
+
+## TRACES
+
+- Windows `MpvBackend` construction in `create_player_backend` → `// TRACES: UR-003 | IR-030`
+- `detect_audio_system` Windows branch → `IR-030`
+- Existing `set_audio_settings` gains Windows coverage → `UR-027, UR-032, UR-033 | DR-030, DR-035, DR-036`
+- Allocate **IR-030** in `requirements.md` ("libmpv integration for Windows audio playback").
+
+## Notes for the implementer
+
+- Do this **after** [libmpv2-migration.md](libmpv2-migration.md) — porting the
+  current dead `libmpv` git pin to a second platform would double the migration
+  work.
+- `libmpv2` has broken its API in every major release (4.0 removed command
+  helpers, 5.0 removed `mpv_node`, 6.0 changed `RenderContext` ownership). Pin an
+  exact version.
+- Only the `render`-feature parts of `libmpv2` concern video; audio-only use does
+  not need it, and disabling the default `render` feature may shrink the build.
+- A parallel Claude session may be active — `git diff` first.

docs/traceability-ci.md

@@ -43,14 +43,26 @@ Extracts all TRACES comments from:
 
 ### 2. Coverage Thresholds
 The workflow checks:
-- **Minimum overall coverage:** 50% (57+ requirements traced)
-- **Requirements by type:**
-  - UR (User): 23+ of 39
-  - IR (Integration): 5+ of 24
-  - DR (Development): 28+ of 48
-  - JA (Jellyfin API): 0+ of 3
+- **Minimum overall coverage:** 50%
 
-If coverage drops below threshold, the workflow **fails** and blocks merge.
+Denominators are **derived from `docs/requirements.md` at run time** — they are
+never hardcoded here or in the workflow. Run `bun run traces:coverage` for the
+current per-type breakdown; any number written into this document is a snapshot
+that will drift.
+
+> **Why this matters.** The workflow used to divide by frozen literals
+> (UR/39, IR/24, DR/48, JA/3, total 114) while `requirements.md` had grown past
+> 200. It reported **158%** coverage, so the 50% threshold was unreachable and
+> the job could not fail regardless of how far coverage dropped. See
+> [specs/traceability-gate-repair.md](specs/traceability-gate-repair.md).
+
+Coverage is the *intersection* of traced and defined IDs: an ID that appears in
+a `TRACES:` comment but is not defined in `requirements.md` is reported as
+**orphaned** and does not count toward coverage. UT/IT test identifiers are a
+separate taxonomy and are excluded entirely.
+
+The workflow **fails** and blocks merge if coverage drops below 50% — or if it
+computes above 100%, which can only mean the gate is miscounting.
 
 ### 3. Modified File Checking
 On pull requests, the workflow:
@@ -153,11 +165,13 @@ cat docs/traceability.md
 ## Coverage Goals
 
 ### Current Status
-- Overall: 51% (56/114)
-- UR: 59% (23/39)
-- IR: 21% (5/24)
-- DR: 58% (28/48)
-- JA: 0% (0/3)
+
+Run `bun run traces:coverage` — it prints the live figure and exits non-zero
+below threshold. Numbers are deliberately not pinned here; the previous snapshot
+in this section (51%, 56/114) was stale by roughly 100 requirements and was what
+made the broken CI arithmetic look plausible for so long.
+
+As of July 2026 overall coverage is ~86% (182/212).
 
 ### Targets
 - **Short term** (Sprint): Maintain ≥50% overall

docs/ux-flows.md

@@ -346,10 +346,12 @@ flowchart TB
 **User Interaction:**
 - **Tap screen:** Controls reappear for 3 seconds
 - **Double tap left side:** Rewind 10 seconds (shows animated feedback with "-10" indicator)
-- **Double tap right side:** Forward 10 seconds (shows animated feedback with "+10" indicator)
+- **Double tap right side:** Forward 30 seconds (shows animated feedback with "+30" indicator)
+- **Single tap play/pause is deferred** by the 300 ms double-tap window, so a double tap
+  skips without also toggling pause (UR-061)
 - **Swipe up/down on left side:** Adjust brightness (0.3-1.7x, shows brightness indicator with progress bar)
 - **Swipe up/down on right side:** Adjust volume (0-100%, shows volume indicator with progress bar)
-- **Keyboard arrows:** ← rewind 10s, → forward 10s (desktop/external keyboard)
+- **Keyboard arrows:** ← rewind 10s, → forward 30s (desktop/external keyboard)
 - **Keyboard space/K:** Toggle play/pause
 - **Keyboard F:** Toggle fullscreen
 - **Pinch:** Zoom (planned)

package.json

@@ -1,6 +1,6 @@
 {
   "name": "jellytau",
-  "version": "0.1.2",
+  "version": "0.2.9",
   "description": "",
   "type": "module",
   "packageManager": "bun@1.3.5",
@@ -20,6 +20,8 @@
     "check:boundary": "bash scripts/check-frontend-boundary.sh",
     "android:build": "./scripts/build-android.sh",
     "android:build:release": "./scripts/build-android.sh release",
+    "android:build:device": "./scripts/build-android.sh --device",
+    "android:build:release:device": "./scripts/build-android.sh release --device",
     "android:build:clean": "rm -rf node_modules/.vite dist .svelte-kit .next build target src-tauri/target && bun install && bun run build",
     "android:deploy": "./scripts/deploy-android.sh",
     "android:dev": "./scripts/build-and-deploy.sh",
@@ -36,6 +38,7 @@
     "traces": "bun run scripts/extract-traces.ts",
     "traces:json": "bun run scripts/extract-traces.ts --format json",
     "traces:markdown": "bun run scripts/extract-traces.ts --format markdown > docs/traceability.md",
+    "traces:coverage": "bun run scripts/extract-traces.ts --format coverage",
     "release:notes": "bun run scripts/release-notes.ts"
   },
   "license": "MIT",

scripts/README.md

@@ -69,13 +69,29 @@ Extract requirement IDs (TRACES) from source code and generate a traceability ma
 bun run traces                    # Generate markdown report
 bun run traces:json              # Generate JSON report
 bun run traces:markdown           # Save to docs/traceability.md
+bun run traces:coverage           # Coverage gate — exits non-zero below 50%
 ```
 
-The script scans all TypeScript, Svelte, and Rust files looking for `TRACES:` comments and generates a comprehensive mapping of:
+The script scans all TypeScript, Svelte, and Rust files (plus `scripts/`)
+looking for `TRACES:` comments and generates a comprehensive mapping of:
 - Which code files implement which requirements
 - Line numbers and code context
 - Coverage summary by requirement type (UR, IR, DR, JA)
 
+**`bun run traces:coverage` is the supported way to check requirement coverage
+locally** — it runs the same computation CI does. Coverage denominators are
+derived from `docs/requirements.md` at run time; they are never hardcoded. An ID
+that appears in a `TRACES:` comment but is not defined in `requirements.md` is
+reported as *orphaned* and does not count toward coverage (see DR-093).
+
+> **Removed:** `check-req-coverage.sh`, `check-test-coverage.sh`, and
+> `find-req-implementations.sh` were deleted in July 2026. They read an
+> undocumented `@req:` tag convention parallel to `TRACES:`, grepped `src-tauri/`
+> unscoped (hanging on ~40 GB of `target/` artifacts), and in one case reported
+> "all requirements implemented" from an empty result set. `extract-traces.ts` is
+> the single source of truth for requirement coverage. See
+> [docs/specs/req-coverage-script-removal.md](../docs/specs/req-coverage-script-removal.md).
+
 Example TRACES comment in code:
 ```typescript
 // TRACES: UR-005, UR-026 | DR-029

scripts/build-android.sh

@@ -18,15 +18,50 @@ echo ""
 # Parse args: build type (debug/release) and optional --clean flag.
 # By default the build is INCREMENTAL — Cargo and Vite reuse their caches.
 # Pass --clean (or CLEAN=1) to wipe all caches for a from-scratch build.
+#
+# ABI selection: by default Tauri builds all four ABIs (arm64/arm/x86/x86_64),
+# which is what a distributable universal APK needs — but for an on-device test
+# it means three wasted Rust compiles. Pass --device (or ABI=aarch64) to build
+# only the connected device's architecture; --abi <t> targets one explicitly.
 BUILD_TYPE="debug"
 CLEAN="${CLEAN:-0}"
+ABI="${ABI:-}"
+next_is_abi=0
 for arg in "$@"; do
+    if [ "$next_is_abi" = "1" ]; then
+        ABI="$arg"
+        next_is_abi=0
+        continue
+    fi
     case "$arg" in
         --clean) CLEAN=1 ;;
+        --abi) next_is_abi=1 ;;
+        --device) ABI="device" ;;
         debug|release) BUILD_TYPE="$arg" ;;
     esac
 done
 
+# Resolve --device to the attached device's Rust target triple.
+if [ "$ABI" = "device" ]; then
+    device_abi="$(adb shell getprop ro.product.cpu.abi 2>/dev/null | tr -d '\r\n')"
+    case "$device_abi" in
+        arm64-v8a)   ABI="aarch64" ;;
+        armeabi-v7a) ABI="armv7" ;;
+        x86_64)      ABI="x86_64" ;;
+        x86)         ABI="i686" ;;
+        *)
+            echo "⚠️  Could not detect device ABI (got '${device_abi:-none}') — building all targets."
+            ABI=""
+            ;;
+    esac
+    [ -n "$ABI" ] && echo "🎯 Device ABI $device_abi → building only '$ABI'"
+fi
+
+TARGET_ARGS=()
+if [ -n "$ABI" ]; then
+    TARGET_ARGS=(--target "$ABI")
+fi
+
 # Step 0: Optionally clear build caches for a fully fresh build.
 if [ "$CLEAN" = "1" ]; then
     echo "🧹 Clearing build caches (clean build)..."
@@ -48,10 +83,10 @@ if [ "$BUILD_TYPE" = "release" ]; then
     # after sync-android-sources.sh, since gen/android is (re)generated there.
     ./scripts/write-keystore-properties.sh
     echo "📦 Building release APK..."
-    bun run tauri android build --apk true
+    bun run tauri android build --apk true "${TARGET_ARGS[@]}"
 else
     echo "📦 Building debug APK..."
-    bun run tauri android build --apk true --debug
+    bun run tauri android build --apk true --debug "${TARGET_ARGS[@]}"
 fi
 
 echo ""

scripts/check-frontend-boundary.sh

@@ -1,6 +1,8 @@
 #!/usr/bin/env bash
 # Boundary tripwire: flag domain-taxonomy leaks in the Svelte frontend.
 #
+# Implements DR-094 (see docs/requirements.md).
+#
 # The project rule (CLAUDE.md, docs/architecture/02-svelte-frontend.md) is that
 # the frontend is presentation-only and the Rust backend owns domain logic —
 # including Jellyfin's item-type *taxonomy* (what the category "Music" means as a
@@ -9,18 +11,29 @@
 #
 # ⚠️ This is a TRIPWIRE, NOT A PROOF. A grep cannot distinguish taxonomy-as-policy
 # (a leak) from taxonomy-as-display (legitimate: "is this a music card?"). It
-# targets the one machine-detectable signature of the leak class — a *query* that
-# names a multi-type category — and defers everything subtler to the human
-# spec-review checklist (docs/specs/SPEC-REVIEW-CHECKLIST.md). A clean run here
-# does not mean the boundary is respected; it means the crudest violation isn't
-# present.
+# targets the machine-detectable signature of the leak class and defers
+# everything subtler to the human spec-review checklist
+# (docs/specs/SPEC-REVIEW-CHECKLIST.md). A clean run here does not mean the
+# boundary is respected; it means the crudest violation isn't present.
 #
-# What it flags: an `includeItemTypes: [ ... , ... ]` array literal with two or
-# more types — i.e. the frontend deciding that a *category* maps to a *set* of
-# Jellyfin types, which is domain knowledge the backend should own. Single-type
-# query arrays (`includeItemTypes: ["Movie"]`) are a page saying "I show movies"
-# and are allowed. Type *inspection* (`item.type === "Audio"`) is display logic
-# and is not matched.
+# What it flags: an array literal naming two or more Jellyfin item types,
+# ANYWHERE in src/ — i.e. the frontend deciding that a *category* maps to a *set*
+# of Jellyfin types, which is domain knowledge the backend should own.
+# Single-type arrays (`includeItemTypes: ["Movie"]`) are a page saying "I show
+# movies" and are allowed. Type *inspection* (`item.type === "Audio"`) is display
+# logic and is not matched.
+#
+# 🔴 What it still CANNOT see (do not read a green run as proof):
+#   - a type set built at run time:      [...musicTypes, "Playlist"]
+#   - types split across variables:      const A = "Audio"; [A, B]
+#   - taxonomy as control flow:          switch (t) { case "Audio": … }
+#                                        t === "Audio" || t === "MusicAlbum"
+#   - an item type absent from ITEM_TYPES below (false negative by design)
+#
+# This check was hardened in July 2026 after the audit found it passing on the
+# very leak it was written for: the original pattern was anchored to
+# `includeItemTypes:` at the query site, so assigning the same array to a named
+# const evaded it entirely. See docs/specs/boundary-tripwire-hardening.md (DR-094).
 #
 # Escaping a genuine exception: add the file+reason to the ALLOWLIST below.
 
@@ -28,7 +41,7 @@ set -euo pipefail
 
 cd "$(dirname "$0")/.."
 
-# Files permitted to contain a multi-type includeItemTypes query, with the reason.
+# Files permitted to contain a multi-type item-type array, with the reason.
 # Keep this SHORT. A growing allowlist means the boundary is eroding — that is a
 # signal to push taxonomy into Rust, not to keep appending here.
 ALLOWLIST=(
@@ -36,8 +49,31 @@ ALLOWLIST=(
   # two-type filmography query with no category-configuration behind it. Tracked
   # as acceptable pending any person-scope work; revisit if it grows.
   "src/lib/components/library/PersonDetailView.svelte"
+
+  # Grid styling predicate over `config.itemType`, a value the page already
+  # declares about itself. Selects a *look*, issues no query, and would only
+  # change if the UI were redesigned — presentation, not taxonomy-as-policy.
+  "src/lib/components/library/GenericMediaListPage.svelte"
+
+  # "Is this item a container?" predicate for downloads browsing.
+  # BORDERLINE — leans domain: the container set grows when Jellyfin adds a
+  # container type. TODO: replace with a backend-supplied `MediaItem.isContainer`
+  # flag and remove this entry. Tracked in
+  # docs/specs/boundary-tripwire-hardening.md §Out of scope.
+  "src/lib/components/downloads/DownloadedBrowse.svelte"
 )
 
+# Hard cap so erosion is caught mechanically rather than by whoever notices.
+# Deliberately just above the current count: the next exception forces a
+# conversation instead of a one-line append.
+MAX_ALLOWLIST=4
+
+if [[ "${#ALLOWLIST[@]}" -gt "$MAX_ALLOWLIST" ]]; then
+  echo "❌ Allowlist has ${#ALLOWLIST[@]} entries (max $MAX_ALLOWLIST)."
+  echo "   Push taxonomy into Rust instead of appending here."
+  exit 1
+fi
+
 is_allowed() {
   local file="$1"
   for allowed in "${ALLOWLIST[@]}"; do
@@ -46,11 +82,28 @@ is_allowed() {
   return 1
 }
 
-# Multi-element includeItemTypes array: `includeItemTypes: [ <x> , <y> ... ]`.
-# The comma inside the brackets is what makes it multi-type.
-PATTERN='includeItemTypes:[[:space:]]*\[[^]]*,[^]]*\]'
+# Two or more adjacent Jellyfin item-type string literals inside a bracket.
+#
+# NOT anchored to `includeItemTypes:` — that was the original rule, and it missed
+# the real leak: `searchScope.ts` assigned the same array to a named const and
+# dereferenced it one indirection away from the query, so the grep never saw it
+# while CI stayed green. Matching the array literal itself catches a const, a
+# Record value, a function return, and an inline query alike.
+#
+# Deliberate limits:
+#   - requires TWO adjacent types, so single-type presentation
+#     (`itemType: "Movie"`) stays legal — the rule targets *category* taxonomy;
+#   - requires string literals, so `item.type === "Audio"` (display inspection)
+#     does not match;
+#   - uses an explicit type list rather than a generic capitalised-word pattern,
+#     so unrelated string arrays (`["High","Low"]`) produce no noise.
+#
+# An item type missing from this list is a false *negative*, never a false
+# positive — the check degrades safely as Jellyfin adds types.
+ITEM_TYPES='Movie|Series|Episode|Audio|MusicAlbum|MusicArtist|MusicVideo|Season|BoxSet|Playlist|Book|AudioBook|Video|Person|Folder|CollectionFolder|TvChannel|LiveTvChannel'
+PATTERN="\[[[:space:]]*\"($ITEM_TYPES)\"[[:space:]]*,[[:space:]]*\"($ITEM_TYPES)\""
 
-echo "🔎 Checking frontend for domain-taxonomy leaks (multi-type query arrays)…"
+echo "🔎 Checking frontend for domain-taxonomy leaks (item-type array literals)…"
 
 # Collect hits, excluding tests and the allowlist.
 violations=""
@@ -69,9 +122,11 @@ done < <(grep -rInE "$PATTERN" src/ 2>/dev/null || true)
 
 if [[ -n "$violations" ]]; then
   echo ""
-  echo "❌ Frontend boundary violation: a multi-type includeItemTypes query defines"
-  echo "   a category in the presentation layer. That taxonomy belongs in Rust —"
-  echo "   send an opaque scope and let the backend expand it to item types."
+  echo "❌ Frontend boundary violation: an item-type array literal defines a"
+  echo "   category in the presentation layer. That taxonomy belongs in Rust —"
+  echo "   send an opaque scope/enum and let the backend expand it to item types"
+  echo "   (see SearchScope::item_types() in src-tauri/src/repository/types.rs)."
+  echo "   Assigning the array to a const does not make it presentation."
   echo "   See docs/specs/scoped-search-boundary.md and CLAUDE.md."
   echo ""
   echo "$violations" | sed 's/^/   /'

scripts/check-req-coverage.sh

@@ -1,84 +0,0 @@
-#!/bin/bash
-#
-# Requirements Coverage Checker
-# Extracts @req tags from codebase and compares with README.md
-#
-
-set -e
-
-REQUIREMENTS_FILE="README.md"
-SOURCE_DIRS="src-tauri/ src/"
-
-echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
-echo "  Requirements Coverage Report"
-echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
-echo ""
-
-# Extract requirement IDs from README.md (UR-, IR-, DR-, JA-)
-echo "📊 Scanning requirements from $REQUIREMENTS_FILE..."
-requirements=$(grep -E "^\| (UR|IR|DR|JA)-[0-9]+" "$REQUIREMENTS_FILE" | \
-               sed -E 's/^\| ([A-Z]+-[0-9]+).*/\1/' | \
-               sort -u)
-
-total_reqs=$(echo "$requirements" | wc -l)
-implemented=0
-partial=0
-planned=0
-missing=0
-
-echo ""
-echo "Category Breakdown:"
-echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
-
-for category in UR IR DR JA; do
-    cat_count=$(echo "$requirements" | grep "^$category-" | wc -l)
-    printf "%-4s %3d requirements\n" "$category:" "$cat_count"
-done
-
-echo ""
-echo "Implementation Status:"
-echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
-
-for req in $requirements; do
-    # Count full implementations
-    full_count=$(grep -r "@req: $req" $SOURCE_DIRS 2>/dev/null | grep -v "@req-partial" | grep -v "@req-planned" | wc -l)
-
-    # Count partial implementations
-    partial_count=$(grep -r "@req-partial: $req" $SOURCE_DIRS 2>/dev/null | wc -l)
-
-    # Count planned
-    planned_count=$(grep -r "@req-planned: $req" $SOURCE_DIRS 2>/dev/null | wc -l)
-
-    if [ "$full_count" -gt 0 ]; then
-        echo "✅ $req: $full_count implementation(s)"
-        ((implemented++))
-    elif [ "$partial_count" -gt 0 ]; then
-        echo "🔶 $req: $partial_count partial implementation(s)"
-        ((partial++))
-    elif [ "$planned_count" -gt 0 ]; then
-        echo "📋 $req: Planned (not yet implemented)"
-        ((planned++))
-    else
-        echo "❌ $req: No implementation found"
-        ((missing++))
-    fi
-done
-
-echo ""
-echo "Summary:"
-echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
-printf "Total Requirements:     %3d\n" "$total_reqs"
-printf "✅ Fully Implemented:   %3d (%.0f%%)\n" "$implemented" "$(echo "scale=0; $implemented * 100 / $total_reqs" | bc)"
-printf "🔶 Partially Implemented: %3d (%.0f%%)\n" "$partial" "$(echo "scale=0; $partial * 100 / $total_reqs" | bc)"
-printf "📋 Planned:             %3d (%.0f%%)\n" "$planned" "$(echo "scale=0; $planned * 100 / $total_reqs" | bc)"
-printf "❌ Missing:             %3d (%.0f%%)\n" "$missing" "$(echo "scale=0; $missing * 100 / $total_reqs" | bc)"
-echo ""
-
-# Exit code based on missing critical requirements
-if [ "$missing" -gt 0 ]; then
-    echo "⚠️  Warning: $missing requirements have no implementation"
-    exit 1
-else
-    echo "✨ All requirements have implementations!"
-    exit 0
-fi

scripts/check-test-coverage.sh

@@ -1,40 +0,0 @@
-#!/bin/bash
-#
-# Test Coverage Report
-# Links test requirements to implementations
-#
-
-echo "Test Coverage Report"
-echo "===================="
-echo ""
-
-test_reqs=$(grep -rh "@req-test:" src-tauri/ 2>/dev/null | \
-            sed 's/.*@req-test: \([A-Z][A-Z]-[0-9]*\).*/\1/' | \
-            sort -u)
-
-total_tests=0
-covered=0
-uncovered=0
-
-for req in $test_reqs; do
-    test_count=$(grep -r "@req-test: $req" src-tauri/ 2>/dev/null | wc -l)
-    impl_count=$(grep -r "@req: $req" src-tauri/ src/ 2>/dev/null | wc -l)
-
-    ((total_tests++))
-
-    if [ "$test_count" -gt 0 ] && [ "$impl_count" -gt 0 ]; then
-        echo "✅ $req: $test_count test(s), $impl_count implementation(s)"
-        ((covered++))
-    elif [ "$impl_count" -eq 0 ]; then
-        echo "⚠️  $req: $test_count test(s) but no implementation"
-        ((uncovered++))
-    fi
-done
-
-echo ""
-echo "Summary:"
-echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
-printf "Total Test Requirements: %3d\n" "$total_tests"
-printf "✅ With Implementation:  %3d (%.0f%%)\n" "$covered" "$(echo "scale=0; $covered * 100 / $total_tests" | bc)"
-printf "⚠️  No Implementation:   %3d (%.0f%%)\n" "$uncovered" "$(echo "scale=0; $uncovered * 100 / $total_tests" | bc)"
-echo ""

scripts/extract-traces.test.ts

@@ -0,0 +1,182 @@
+/**
+ * Tests for the traceability coverage computation.
+ *
+ * These run over fixture strings rather than the live docs/requirements.md, so
+ * their meaning does not drift as requirements are added.
+ *
+ * Background: the CI gate divided traced-requirement counts by hardcoded
+ * denominators (UR/39, IR/24, DR/48, JA/3, total 114) that had fallen out of
+ * date, reporting 158% coverage and making the 50% threshold unreachable. These
+ * tests pin the parsing and arithmetic that replace those literals.
+ *
+ * @req-test: UT-089 - Requirement definitions parsed from requirements.md
+ * @req-test: UT-090 - Coverage is the intersection of traced and defined IDs
+ */
+
+import { describe, it, expect } from "vitest";
+import { countDefinedRequirements, computeCoverage } from "./extract-traces";
+
+describe("countDefinedRequirements", () => {
+  it("counts a well-formed table row as a defined requirement", () => {
+    const md = `
+| ID | Requirement | Priority | Status |
+|----|-------------|----------|--------|
+| UR-001 | Run the app on multiple platforms | High | In Progress |
+| UR-002 | Access media when online or offline | High | Done |
+`;
+    const defined = countDefinedRequirements(md);
+    expect(defined.UR).toBe(2);
+    expect(defined.DR).toBe(0);
+  });
+
+  it("does not count IDs that appear only in the Traces To column", () => {
+    // The bug this rule avoids: a naive grep for /DR-\d{3}/ over the whole file
+    // counts DR-001 here as "defined", inflating the denominator with IDs that
+    // are merely referenced.
+    const md = `
+| DR-001 | Player state machine | Player | UR-005 | Done |
+| DR-002 | MediaItem struct | Player | UR-003, UR-004 | Done |
+`;
+    const defined = countDefinedRequirements(md);
+    expect(defined.DR).toBe(2);
+    // UR-005/UR-003/UR-004 are referenced, never defined here.
+    expect(defined.UR).toBe(0);
+  });
+
+  it("does not count IDs mentioned in prose", () => {
+    const md = `
+Some prose explaining that UR-005 relates to DR-001 and JA-002.
+
+| UR-005 | Control media playback | High | Done |
+`;
+    const defined = countDefinedRequirements(md);
+    expect(defined.UR).toBe(1);
+    expect(defined.DR).toBe(0);
+    expect(defined.JA).toBe(0);
+  });
+
+  it("deduplicates an ID listed in both the spec table and the traceability matrix", () => {
+    // requirements.md lists every UR twice: once in §1 (definition) and again in
+    // §3 (traceability matrix), both as a leading table cell. Counting rows
+    // instead of unique IDs double-counts the UR denominator (121 vs 61).
+    const md = `
+| UR-005 | Control media playback | High | Done |
+| UR-006 | Browse the library | High | Done |
+
+### Traceability Matrix
+
+| UR-005 | - | DR-001, DR-005, DR-009 |
+| UR-006 | - | DR-012 |
+`;
+    const defined = countDefinedRequirements(md);
+    expect(defined.UR).toBe(2);
+  });
+
+  it("collects the defined ID set, not just counts", () => {
+    const md = `
+| UR-001 | A | High | Done |
+| DR-050 | B | Player | UR-001 | Done |
+`;
+    const defined = countDefinedRequirements(md);
+    expect(defined.ids.has("UR-001")).toBe(true);
+    expect(defined.ids.has("DR-050")).toBe(true);
+    expect(defined.ids.has("UR-999")).toBe(false);
+  });
+});
+
+describe("computeCoverage", () => {
+  const defined = {
+    UR: 2,
+    IR: 0,
+    DR: 2,
+    JA: 0,
+    total: 4,
+    ids: new Set(["UR-001", "UR-002", "DR-001", "DR-002"]),
+  };
+
+  it("computes coverage as traced ∩ defined over defined", () => {
+    const traced = ["UR-001", "DR-001"];
+    const cov = computeCoverage(traced, defined);
+    expect(cov.covered).toBe(2);
+    expect(cov.total).toBe(4);
+    expect(cov.percent).toBe(50);
+  });
+
+  it("does not let a traced-but-undefined ID inflate the numerator", () => {
+    // This is how a ratio exceeds 100%: a TRACES comment naming a typo'd or
+    // deleted requirement counted as covered.
+    const traced = ["UR-001", "DR-001", "DR-097"];
+    const cov = computeCoverage(traced, defined);
+    expect(cov.covered).toBe(2);
+    expect(cov.percent).toBe(50);
+  });
+
+  it("reports traced-but-undefined IDs as orphaned so they get fixed", () => {
+    const traced = ["UR-001", "DR-097", "JA-404"];
+    const cov = computeCoverage(traced, defined);
+    expect(cov.orphaned).toEqual(["DR-097", "JA-404"]);
+  });
+
+  it("has no orphans when every traced ID is defined", () => {
+    const cov = computeCoverage(["UR-001", "UR-002"], defined);
+    expect(cov.orphaned).toEqual([]);
+  });
+
+  it("ignores UT/IT test IDs entirely — they are a separate taxonomy", () => {
+    // UT/IT are defined in §4 of requirements.md, not among the four
+    // requirement types. Treating them as orphans buries real typos in ~60
+    // lines of noise, and counting them would corrupt the ratio.
+    const cov = computeCoverage(["UR-001", "UT-088", "IT-017"], defined);
+    expect(cov.orphaned).toEqual([]);
+    expect(cov.covered).toBe(1);
+  });
+
+  it("reports 0% rather than dividing by zero for an empty trace set", () => {
+    const cov = computeCoverage([], defined);
+    expect(cov.covered).toBe(0);
+    expect(cov.percent).toBe(0);
+  });
+
+  it("reports 0% rather than NaN when nothing is defined", () => {
+    const empty = { UR: 0, IR: 0, DR: 0, JA: 0, total: 0, ids: new Set<string>() };
+    const cov = computeCoverage([], empty);
+    expect(cov.percent).toBe(0);
+    expect(Number.isNaN(cov.percent)).toBe(false);
+  });
+
+  it("reports exactly 100% when all defined requirements are traced, never above", () => {
+    const traced = ["UR-001", "UR-002", "DR-001", "DR-002"];
+    const cov = computeCoverage(traced, defined);
+    expect(cov.percent).toBe(100);
+  });
+
+  it("ignores duplicate traced IDs", () => {
+    const traced = ["UR-001", "UR-001", "UR-001"];
+    const cov = computeCoverage(traced, defined);
+    expect(cov.covered).toBe(1);
+  });
+});
+
+describe("live requirements.md", () => {
+  it("parses the real file to the counts the CI gate must use", () => {
+    // Guards the specific regression: CI hardcoded UR/39, IR/24, DR/48, JA/3
+    // (total 114) while the real file had grown to 211. Update these numbers
+    // deliberately when requirements are added — that edit is the signal the
+    // denominator is live rather than frozen.
+    const fs = require("fs");
+    const path = require("path");
+    // import.meta.dir is Bun-only; derive from import.meta.url under vitest.
+    const here = path.dirname(new URL(import.meta.url).pathname);
+    const md = fs.readFileSync(
+      path.resolve(here, "../docs/requirements.md"),
+      "utf-8"
+    );
+    const defined = countDefinedRequirements(md);
+
+    expect(defined.UR).toBe(61);
+    expect(defined.IR).toBe(29);
+    expect(defined.DR).toBe(96);
+    expect(defined.JA).toBe(32);
+    expect(defined.total).toBe(218);
+  });
+});

scripts/extract-traces.ts

@@ -34,11 +34,20 @@ interface TracesData {
     DR: string[];
     JA: string[];
   };
+  /** Requirements *defined* in requirements.md — the coverage denominators. */
+  defined?: { UR: number; IR: number; DR: number; JA: number; total: number };
+  coverage?: CoverageResult;
 }
 
 // Repo root, derived from this script's location (scripts/ -> repo root).
 // Must NOT be hardcoded to a developer's machine, or CI checkouts see no files.
-const BASE_DIR = path.resolve(import.meta.dir, "..");
+//
+// `import.meta.dir` is a Bun extension and is undefined when this module is
+// imported by vitest (which runs it as an ordinary ESM module), so fall back to
+// import.meta.url — this file must stay importable for extract-traces.test.ts.
+const SCRIPT_DIR =
+  import.meta.dir ?? path.dirname(new URL(import.meta.url).pathname);
+const BASE_DIR = path.resolve(SCRIPT_DIR, "..");
 
 const TRACES_PATTERN = /TRACES:\s*([^\n]+)/gi;
 const REQ_ID_PATTERN = /([A-Z]{2})-(\d{3})/g;
@@ -50,7 +59,10 @@ function extractRequirementIds(tracesString: string): string[] {
 
 function getAllSourceFiles(): string[] {
   const baseDir = BASE_DIR;
-  const patterns = ["src", "src-tauri/src"];
+  // `scripts` is scanned too: build tooling implements requirements (e.g.
+  // DR-093, the coverage engine itself) and would otherwise be invisible to the
+  // very matrix it generates.
+  const patterns = ["src", "src-tauri/src", "scripts"];
   const files: string[] = [];
 
   function walkDir(dir: string) {
@@ -192,6 +204,109 @@ function extractTraces(): TracesData {
   };
 }
 
+// ---------------------------------------------------------------------------
+// Coverage: how many *defined* requirements are actually traced.
+//
+// The denominators MUST be derived from requirements.md, never hardcoded. The
+// CI gate previously divided by frozen literals (UR/39, IR/24, DR/48, JA/3,
+// total 114) while the real file had grown to 211 requirements, so it reported
+// 158% coverage and the 50% threshold became unreachable — the gate could not
+// fail. See docs/specs/traceability-gate-repair.md.
+//
+// TRACES: | DR-093
+// ---------------------------------------------------------------------------
+
+export interface DefinedRequirements {
+  UR: number;
+  IR: number;
+  DR: number;
+  JA: number;
+  total: number;
+  ids: Set<string>;
+}
+
+export interface CoverageResult {
+  covered: number;
+  total: number;
+  percent: number;
+  /** Traced in code but not defined in requirements.md (typo, or deleted req). */
+  orphaned: string[];
+}
+
+/**
+ * A requirement is *defined* only where its ID is the leading cell of a markdown
+ * table row: `| DR-001 | … |`.
+ *
+ * This deliberately ignores IDs in the "Traces To" column and in prose — a
+ * naive scan for /DR-\d{3}/ counts those as definitions and inflates the
+ * denominator. IDs are deduplicated because requirements.md lists each UR twice
+ * (once in §1 as a definition, again in §3's traceability matrix), which would
+ * otherwise double the UR count from 61 to 121.
+ *
+ * TRACES: | DR-093
+ */
+export function countDefinedRequirements(markdown: string): DefinedRequirements {
+  const ids = new Set<string>();
+  const ROW_ID = /^\|\s*(UR|IR|DR|JA)-(\d{3})\s*\|/;
+
+  for (const line of markdown.split("\n")) {
+    const match = line.match(ROW_ID);
+    if (match) ids.add(`${match[1]}-${match[2]}`);
+  }
+
+  const countOf = (type: string) =>
+    [...ids].filter((id) => id.startsWith(`${type}-`)).length;
+
+  return {
+    UR: countOf("UR"),
+    IR: countOf("IR"),
+    DR: countOf("DR"),
+    JA: countOf("JA"),
+    total: ids.size,
+    ids,
+  };
+}
+
+/**
+ * Coverage is the *intersection* of traced and defined IDs over defined IDs.
+ *
+ * Using the raw traced count as the numerator is what lets a ratio exceed 100%:
+ * a TRACES comment naming a requirement that no longer exists would count as
+ * covered. Those IDs are reported as `orphaned` so they get fixed rather than
+ * silently counted or silently dropped.
+ *
+ * TRACES: | DR-093
+ */
+export function computeCoverage(
+  tracedIds: string[],
+  defined: DefinedRequirements
+): CoverageResult {
+  // Only the four *requirement* types participate in coverage. UT/IT are test
+  // identifiers defined in §4 of requirements.md — a different taxonomy, and
+  // flagging them as orphans would bury real typos in ~60 lines of noise.
+  const isRequirement = (id: string) => /^(UR|IR|DR|JA)-\d{3}$/.test(id);
+
+  const traced = new Set(tracedIds.filter(isRequirement));
+  const covered = [...traced].filter((id) => defined.ids.has(id));
+  const orphaned = [...traced].filter((id) => !defined.ids.has(id)).sort();
+
+  return {
+    covered: covered.length,
+    total: defined.total,
+    percent:
+      defined.total === 0
+        ? 0
+        : Math.round((covered.length / defined.total) * 100),
+    orphaned,
+  };
+}
+
+/** Read requirements.md from the repo and count what it defines. */
+export function readDefinedRequirements(): DefinedRequirements {
+  const reqPath = path.join(BASE_DIR, "docs", "requirements.md");
+  return countDefinedRequirements(fs.readFileSync(reqPath, "utf-8"));
+}
+
 function generateMarkdown(data: TracesData): string {
   let md = `# Code Traceability Matrix
 
@@ -265,21 +380,83 @@ function generateJson(data: TracesData): string {
   return JSON.stringify(data, null, 2);
 }
 
-// Main
-const args = Bun.argv.slice(2);
-const format = args.includes("--format")
-  ? args[args.indexOf("--format") + 1]
-  : "markdown";
+/**
+ * Human-readable coverage report; exits non-zero below the threshold so this is
+ * runnable as a local gate (`bun run traces:coverage`), not just in CI.
+ *
+ * TRACES: | DR-093
+ */
+function reportCoverage(data: TracesData, minThreshold: number): number {
+  const defined = data.defined!;
+  const cov = data.coverage!;
 
-console.error("🔍 Extracting TRACES from codebase...");
-const data = extractTraces();
+  const definedIds = readDefinedRequirements().ids;
 
-if (format === "json") {
-  console.log(generateJson(data));
-} else {
-  console.log(generateMarkdown(data));
+  console.log("📋 Requirement coverage (traced / defined):");
+  for (const type of ["UR", "IR", "DR", "JA"] as const) {
+    const traced = data.byType[type].filter((id) => definedIds.has(id)).length;
+    console.log(`   ${type}: ${traced} / ${defined[type]}`);
+  }
+  console.log("");
+  console.log(`📈 Overall: ${cov.covered} / ${cov.total} (${cov.percent}%)`);
+
+  if (cov.orphaned.length > 0) {
+    console.log("");
+    console.log(
+      `⚠️  Traced but not defined in requirements.md: ${cov.orphaned.join(", ")}`
+    );
+    console.log("   Fix the TRACES comment or add the requirement.");
+  }
+
+  // A ratio above 100% means the computation is broken (the condition that hid
+  // the stale-denominator bug for so long). Fail loudly rather than report it.
+  if (cov.percent > 100) {
+    console.log("");
+    console.log(`❌ Coverage > 100% — the gate is miscomputing.`);
+    return 1;
+  }
+
+  if (cov.percent < minThreshold) {
+    console.log("");
+    console.log(`❌ Coverage (${cov.percent}%) is below minimum (${minThreshold}%)`);
+    return 1;
+  }
+
+  console.log("");
+  console.log(`✅ Coverage is acceptable (${cov.percent}% >= ${minThreshold}%)`);
+  return 0;
 }
 
-console.error(
-  `\n✅ Complete! Found ${data.totalTraces} TRACES across ${data.totalFiles} files`
-);
+// Main — guarded so this module stays importable from extract-traces.test.ts.
+if (import.meta.main) {
+  const args = process.argv.slice(2);
+  const format = args.includes("--format")
+    ? args[args.indexOf("--format") + 1]
+    : "markdown";
+
+  console.error("🔍 Extracting TRACES from codebase...");
+  const data = extractTraces();
+
+  const defined = readDefinedRequirements();
+  const allTraced = Object.keys(data.requirements);
+  data.defined = {
+    UR: defined.UR,
+    IR: defined.IR,
+    DR: defined.DR,
+    JA: defined.JA,
+    total: defined.total,
+  };
+  data.coverage = computeCoverage(allTraced, defined);
+
+  if (format === "json") {
+    console.log(generateJson(data));
+  } else if (format === "coverage") {
+    process.exit(reportCoverage(data, 50));
+  } else {
+    console.log(generateMarkdown(data));
+  }
+
+  console.error(
+    `\n✅ Complete! Found ${data.totalTraces} TRACES across ${data.totalFiles} files`
+  );
+}

scripts/find-req-implementations.sh

@@ -1,56 +0,0 @@
-#!/bin/bash
-#
-# Find all files implementing a specific requirement
-#
-# Usage: ./find-req-implementations.sh UR-004
-#
-
-if [ $# -eq 0 ]; then
-    echo "Usage: $0 <REQUIREMENT_ID>"
-    echo "Example: $0 UR-004"
-    exit 1
-fi
-
-REQ_ID=$1
-
-echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
-echo "  Implementations of $REQ_ID"
-echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
-echo ""
-
-# Full implementations
-echo "Full Implementations:"
-echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
-grep -rn "@req: $REQ_ID" src-tauri/ src/ 2>/dev/null | \
-    grep -v "@req-partial" | \
-    grep -v "@req-planned" | \
-    sed 's/src-tauri\/src\///' | \
-    sed 's/src\///' || echo "  (none)"
-
-echo ""
-
-# Partial implementations
-echo "Partial Implementations:"
-echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
-grep -rn "@req-partial: $REQ_ID" src-tauri/ src/ 2>/dev/null | \
-    sed 's/src-tauri\/src\///' | \
-    sed 's/src\///' || echo "  (none)"
-
-echo ""
-
-# Planned
-echo "Planned Implementations:"
-echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
-grep -rn "@req-planned: $REQ_ID" src-tauri/ src/ 2>/dev/null | \
-    sed 's/src-tauri\/src\///' | \
-    sed 's/src\///' || echo "  (none)"
-
-echo ""
-
-# Tests
-echo "Test Cases:"
-echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
-grep -rn "@req-test: $REQ_ID" src-tauri/ 2>/dev/null | \
-    sed 's/src-tauri\/src\///' || echo "  (none)"
-
-echo ""

scripts/test-all.sh

@@ -7,7 +7,7 @@ echo "🧪 Running all tests..."
 echo ""
 
 echo "📦 Running frontend tests..."
-bun run test
+bun run test --run
 
 echo ""
 echo "🦀 Running Rust tests..."
@@ -15,5 +15,12 @@ cd src-tauri
 cargo test
 cd ..
 
+echo ""
+echo "🚧 Checking architectural gates..."
+# Boundary tripwire (DR-094): no Jellyfin taxonomy in the presentation layer.
+bun run check:boundary
+# Traceability coverage (DR-093): fails below 50%, or above 100% (miscount).
+bun run traces:coverage
+
 echo ""
 echo "✅ All tests passed!"

src-tauri/Cargo.lock

@@ -1994,7 +1994,7 @@ dependencies = [
 
 [[package]]
 name = "jellytau"
-version = "0.1.2"
+version = "0.2.9"
 dependencies = [
  "aes-gcm",
  "async-trait",

src-tauri/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "jellytau"
-version = "0.1.2"
+version = "0.2.9"
 description = "A Tauri App"
 authors = ["you"]
 edition = "2021"

src-tauri/android/src/main/java/com/dtourolle/jellytau/MainActivity.kt

@@ -1,10 +1,5 @@
 package com.dtourolle.jellytau
 
-import android.content.Context
-import android.media.AudioAttributes
-import android.media.AudioFocusRequest
-import android.media.AudioManager
-import android.os.Build
 import android.os.Bundle
 import android.os.Handler
 import android.os.Looper
@@ -19,8 +14,6 @@ class MainActivity : TauriActivity() {
   private val handler = Handler(Looper.getMainLooper())
   private var configAttempts = 0
   private val maxConfigAttempts = 10
-  private var audioFocusRequest: AudioFocusRequest? = null
-  private val audioManager by lazy { getSystemService(Context.AUDIO_SERVICE) as AudioManager }
 
   /**
    * Coarse override for whether backgrounding the app should auto-enter PiP.
@@ -50,6 +43,15 @@ class MainActivity : TauriActivity() {
    */
   private var mediaWebView: WebView? = null
 
+  /**
+   * The WebView the @JavascriptInterface bridges have been injected into.
+   *
+   * addJavascriptInterface must run once per WebView instance: re-injecting
+   * over an already-loaded page hands JS a stale proxy whose methods are gone.
+   * Compared by identity so a genuinely new WebView still gets its bridges.
+   */
+  private var bridgesInstalledOn: WebView? = null
+
   override fun onCreate(savedInstanceState: Bundle?) {
     enableEdgeToEdge()
     super.onCreate(savedInstanceState)
@@ -159,19 +161,36 @@ class MainActivity : TauriActivity() {
       android.util.Log.d("MainActivity", "WebView found! Configuring settings...")
       mediaWebView = webView
 
-      // Add JavaScript interface for audio focus control
-      webView.addJavascriptInterface(object : Any() {
-        @JavascriptInterface
-        fun requestAudioFocus() {
-          handler.post { this@MainActivity.requestAudioFocus() }
-        }
+      // Register the @JavascriptInterface bridges EXACTLY ONCE per WebView.
+      //
+      // configureWebViewForMedia() runs from onCreate's delayed post AND from
+      // every onResume (plus each WebView re-find), so this used to re-inject
+      // all four bridges repeatedly - 5 times in a 45s session. WebView binds
+      // injected objects at page-load time; re-injecting over a live page
+      // leaves JS holding a stale proxy. The object stays truthy while its
+      // methods vanish, which surfaced as a flood of
+      // "WebView: Unknown object" chromium errors and, in JS,
+      // "TypeError: setEnabled is not a function".
+      //
+      // The visible bug: the background-audio toggle turned blue but never
+      // reached native, so backgroundAudioEnabled stayed false, onStop never
+      // dispatched 'jellytau-background', and a locked screen killed audio
+      // instantly (UR-040). Audio focus and PiP broke the same way.
+      //
+      // The settings/WebChromeClient work below is idempotent and must keep
+      // running on resume; only the bridge injection is one-shot.
+      if (webView === bridgesInstalledOn) {
+        android.util.Log.d("MainActivity", "JS bridges already installed on this WebView - skipping re-injection")
+        configureWebViewSettings(webView)
+        return
+      }
+      bridgesInstalledOn = webView
 
-        @JavascriptInterface
-        fun abandonAudioFocus() {
-          handler.post { this@MainActivity.abandonAudioFocus() }
-        }
-      }, "AndroidAudioFocus")
-      android.util.Log.d("MainActivity", "JavaScript interface 'AndroidAudioFocus' added")
+      // NOTE: there is deliberately no "AndroidAudioFocus" bridge. Manual focus
+      // requests from the WebView competed with Chromium's own
+      // AudioFocusDelegate and with ExoPlayer, and the resulting
+      // AUDIOFOCUS_LOSS paused playback. See the comment on the video listeners
+      // in configureWebViewSettings().
 
       // Add JavaScript interface for picture-in-picture control.
       // enterPip/canEnterPip must run on the main thread; @JavascriptInterface
@@ -212,10 +231,6 @@ class MainActivity : TauriActivity() {
           backgroundAudioEnabled = enabled
           android.util.Log.d("MainActivity", "backgroundAudioEnabled = $enabled")
         }
-
-        /** Whether background audio is available on this device (needs PiP-era APIs unnecessary; audio service always present on Android). */
-        @JavascriptInterface
-        fun isSupported(): Boolean = true
       }, "AndroidBackgroundAudio")
       android.util.Log.d("MainActivity", "JavaScript interface 'AndroidBackgroundAudio' added")
 
@@ -248,6 +263,21 @@ class MainActivity : TauriActivity() {
         dispatchWebEvent("jellytau-network-changed")
       }
 
+      configureWebViewSettings(webView)
+
+    } catch (e: Exception) {
+      android.util.Log.e("MainActivity", "Failed to configure WebView for media", e)
+    }
+  }
+
+  /**
+   * WebView settings, chrome client and the video-unmute script.
+   *
+   * Split out from the bridge injection because this half is idempotent and
+   * must re-run on every resume, whereas addJavascriptInterface must not.
+   */
+  private fun configureWebViewSettings(webView: WebView) {
+    try {
       // Set WebChromeClient to handle video playback and audio focus
       webView.webChromeClient = object : WebChromeClient() {
         override fun onShowCustomView(view: View?, callback: CustomViewCallback?) {
@@ -259,6 +289,21 @@ class MainActivity : TauriActivity() {
           super.onHideCustomView()
           android.util.Log.d("MainActivity", "Video exited fullscreen")
         }
+
+        /**
+         * Forward WebView console output to logcat under the "JellyTauWeb" tag.
+         *
+         * Without this the frontend is invisible to `adb logcat`, which makes
+         * diagnosing anything that spans the JS/native boundary (the
+         * background-audio handoff in particular) guesswork.
+         */
+        override fun onConsoleMessage(msg: android.webkit.ConsoleMessage): Boolean {
+          android.util.Log.d(
+            "JellyTauWeb",
+            "${msg.message()} (${msg.sourceId()}:${msg.lineNumber()})"
+          )
+          return true
+        }
       }
       android.util.Log.d("MainActivity", "WebChromeClient configured")
 
@@ -287,29 +332,18 @@ class MainActivity : TauriActivity() {
               video.volume = 1.0;
               console.log('[Android] Video unmuted, volume:', video.volume, 'muted:', video.muted);
 
-              // Add event listeners to manage audio focus
-              video.addEventListener('play', function() {
-                console.log('[Android] Video play event - requesting audio focus');
-                if (typeof AndroidAudioFocus !== 'undefined') {
-                  AndroidAudioFocus.requestAudioFocus();
-                }
-                console.log('[Android] Video state - muted:', this.muted, 'volume:', this.volume);
-              });
-
-              video.addEventListener('pause', function() {
-                console.log('[Android] Video pause event - abandoning audio focus');
-                if (typeof AndroidAudioFocus !== 'undefined') {
-                  AndroidAudioFocus.abandonAudioFocus();
-                }
-              });
-
-              video.addEventListener('ended', function() {
-                console.log('[Android] Video ended event - abandoning audio focus');
-                if (typeof AndroidAudioFocus !== 'undefined') {
-                  AndroidAudioFocus.abandonAudioFocus();
-                }
-              });
-
+              // NOTE: deliberately no audio-focus calls here.
+              //
+              // WebView already manages audio focus for <video> through
+              // Chromium's own AudioFocusDelegate. Requesting AUDIOFOCUS_GAIN
+              // again from MainActivity made two requesters compete inside one
+              // uid: the grant was immediately followed by AUDIOFOCUS_LOSS
+              // (~45ms), whose handler paused playback - so arming background
+              // audio, or simply pressing play, paused the video in a loop.
+              //
+              // ExoPlayer is the third potential owner and stays authoritative
+              // for native playback (JellyTauPlayer manages its own focus).
+              // Leave focus to whichever engine is actually rendering.
               video.addEventListener('volumechange', function() {
                 console.log('[Android] Video volume changed - volume:', this.volume, 'muted:', this.muted);
               });
@@ -356,48 +390,4 @@ class MainActivity : TauriActivity() {
     return null
   }
 
-  private fun requestAudioFocus() {
-    android.util.Log.d("MainActivity", "Requesting audio focus for video playback")
-
-    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
-      val audioAttributes = AudioAttributes.Builder()
-        .setUsage(AudioAttributes.USAGE_MEDIA)
-        .setContentType(AudioAttributes.CONTENT_TYPE_MOVIE)
-        .build()
-
-      audioFocusRequest = AudioFocusRequest.Builder(AudioManager.AUDIOFOCUS_GAIN)
-        .setAudioAttributes(audioAttributes)
-        .setAcceptsDelayedFocusGain(true)
-        .setOnAudioFocusChangeListener { focusChange ->
-          android.util.Log.d("MainActivity", "Audio focus changed: $focusChange")
-        }
-        .build()
-
-      val result = audioManager.requestAudioFocus(audioFocusRequest!!)
-      android.util.Log.d("MainActivity", "Audio focus request result: $result")
-    } else {
-      @Suppress("DEPRECATION")
-      val result = audioManager.requestAudioFocus(
-        { focusChange ->
-          android.util.Log.d("MainActivity", "Audio focus changed: $focusChange")
-        },
-        AudioManager.STREAM_MUSIC,
-        AudioManager.AUDIOFOCUS_GAIN
-      )
-      android.util.Log.d("MainActivity", "Audio focus request result (legacy): $result")
-    }
-  }
-
-  private fun abandonAudioFocus() {
-    android.util.Log.d("MainActivity", "Abandoning audio focus")
-
-    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
-      audioFocusRequest?.let {
-        audioManager.abandonAudioFocusRequest(it)
-      }
-    } else {
-      @Suppress("DEPRECATION")
-      audioManager.abandonAudioFocus { }
-    }
-  }
 }

src-tauri/android/src/main/java/com/dtourolle/jellytau/player/JellyTauPlayer.kt

@@ -36,6 +36,53 @@ class JellyTauPlayer(private val appContext: Context) {
         /** Position update interval in milliseconds */
         private const val POSITION_UPDATE_INTERVAL_MS = 250L
 
+        /** AudioEffect priority. Positive = higher priority than the default. */
+        private const val EFFECT_PRIORITY = 1000
+
+        /**
+         * Canonical 10-band ISO centre frequencies (Hz), mirroring EQ_BANDS in
+         * settings.rs. Kept in sync deliberately: Rust owns the band layout, this
+         * is only the lookup table used to map those gains onto whatever bands
+         * the device's equalizer actually has.
+         */
+        private val CANONICAL_BAND_CENTRES_HZ =
+            intArrayOf(31, 62, 125, 250, 500, 1000, 2000, 4000, 8000, 16000)
+
+        /**
+         * Map canonical band gains onto a device's band centres by nearest
+         * centre frequency.
+         *
+         * Pure function so it can be unit-tested without a device — device band
+         * counts vary (commonly 5) and getting this wrong silently mis-shapes the
+         * EQ curve rather than failing.
+         *
+         * TRACES: UR-027 | DR-030
+         */
+        @JvmStatic
+        fun resampleBands(
+            canonicalGains: FloatArray,
+            canonicalCentresHz: IntArray,
+            deviceCentresHz: IntArray
+        ): FloatArray {
+            if (canonicalGains.isEmpty() || deviceCentresHz.isEmpty()) {
+                return FloatArray(deviceCentresHz.size)
+            }
+            val usable = minOf(canonicalGains.size, canonicalCentresHz.size)
+            return FloatArray(deviceCentresHz.size) { d ->
+                val target = deviceCentresHz[d]
+                var nearest = 0
+                var bestDelta = Int.MAX_VALUE
+                for (c in 0 until usable) {
+                    val delta = kotlin.math.abs(canonicalCentresHz[c] - target)
+                    if (delta < bestDelta) {
+                        bestDelta = delta
+                        nearest = c
+                    }
+                }
+                canonicalGains[nearest]
+            }
+        }
+
         /** Singleton instance for JNI access */
         @Volatile
         private var instance: JellyTauPlayer? = null
@@ -135,6 +182,18 @@ class JellyTauPlayer(private val appContext: Context) {
     private val coroutineScope = CoroutineScope(Dispatchers.Main + SupervisorJob())
     private var positionUpdateJob: Job? = null
 
+    /** Graphic EQ bound to the current audio session, or null if not attached. */
+    private var equalizer: android.media.audiofx.Equalizer? = null
+
+    /** Loudness/normalization effect bound to the current audio session. */
+    private var loudnessEnhancer: android.media.audiofx.LoudnessEnhancer? = null
+
+    /**
+     * Last settings pushed from Rust, replayed when the audio session is rebuilt.
+     * Held as the raw payload so re-application needs no second parse contract.
+     */
+    private var lastAudioSettings: org.json.JSONObject? = null
+
     /** Current media ID being played */
     private var currentMediaId: String? = null
 
@@ -334,6 +393,11 @@ class JellyTauPlayer(private val appContext: Context) {
 
             override fun onAudioSessionIdChanged(audioSessionId: Int) {
                 android.util.Log.d("JellyTauPlayer", "▶▶▶ AUDIO SESSION ID CHANGED: $audioSessionId")
+                // ExoPlayer rebuilt its audio sink (e.g. on a format change), so
+                // effects bound to the old session are dead. Re-attach, or the EQ
+                // silently stops applying mid-queue.
+                releaseAudioEffects()
+                lastAudioSettings?.let { applyAudioEffects(it) }
             }
         })
     }
@@ -416,6 +480,133 @@ class JellyTauPlayer(private val appContext: Context) {
         }
     }
 
+    /**
+     * Apply audio settings pushed from Rust as JSON.
+     *
+     * Rust owns *what* the values are (band layout, preset curves, normalization
+     * presets); this owns *when* the Android AudioEffect objects exist, since
+     * that needs the live audio session id and must survive a sink rebuild.
+     *
+     * Posted to the main handler rather than run inline: AudioEffect construction
+     * from a player callback can re-enter the player and deadlock.
+     *
+     * TRACES: UR-027, UR-032, UR-033 | DR-030, DR-035, DR-036
+     */
+    fun setAudioSettings(json: String) {
+        mainHandler.post {
+            try {
+                val settings = org.json.JSONObject(json)
+                lastAudioSettings = settings
+
+                // Gapless: ExoPlayer is gapless by default for compatible
+                // formats, so honouring the setting means disabling it when off.
+                exoPlayer.pauseAtEndOfMediaItems = !settings.optBoolean("gaplessPlayback", true)
+
+                applyAudioEffects(settings)
+            } catch (e: Exception) {
+                android.util.Log.e("JellyTauPlayer", "Failed to apply audio settings", e)
+            }
+        }
+    }
+
+    /** Attach/update the EQ and loudness effects for the current audio session. */
+    private fun applyAudioEffects(settings: org.json.JSONObject) {
+        val sessionId = exoPlayer.audioSessionId
+        if (sessionId == C.AUDIO_SESSION_ID_UNSET) {
+            // No sink yet; onAudioSessionIdChanged will re-drive this.
+            return
+        }
+
+        try {
+            applyEqualizer(sessionId, settings)
+        } catch (e: Exception) {
+            android.util.Log.e("JellyTauPlayer", "Equalizer unavailable on this device", e)
+        }
+
+        try {
+            applyNormalization(sessionId, settings)
+        } catch (e: Exception) {
+            android.util.Log.e("JellyTauPlayer", "LoudnessEnhancer unavailable on this device", e)
+        }
+    }
+
+    private fun applyEqualizer(sessionId: Int, settings: org.json.JSONObject) {
+        val enabled = settings.optBoolean("equalizerEnabled", false)
+
+        if (!enabled) {
+            equalizer?.enabled = false
+            return
+        }
+
+        val eq = equalizer ?: android.media.audiofx.Equalizer(EFFECT_PRIORITY, sessionId).also {
+            equalizer = it
+        }
+
+        val bandsJson = settings.optJSONArray("equalizerBands")
+        val canonicalGains = FloatArray(bandsJson?.length() ?: 0) { i ->
+            bandsJson!!.optDouble(i, 0.0).toFloat()
+        }
+        if (canonicalGains.isEmpty()) {
+            eq.enabled = false
+            return
+        }
+
+        // The device's band count/centres are device-dependent (commonly 5) and
+        // will not match our canonical 10-band ISO layout, so resample.
+        val deviceBandCount = eq.numberOfBands.toInt()
+        val deviceCentresHz = IntArray(deviceBandCount) { i ->
+            eq.getCenterFreq(i.toShort()) / 1000 // device reports milliHertz
+        }
+        val levelRange = eq.bandLevelRange // millibels, [min, max]
+
+        val resampled = resampleBands(canonicalGains, CANONICAL_BAND_CENTRES_HZ, deviceCentresHz)
+
+        for (i in 0 until deviceBandCount) {
+            val millibels = (resampled[i] * 100f)
+                .coerceIn(levelRange[0].toFloat(), levelRange[1].toFloat())
+            eq.setBandLevel(i.toShort(), millibels.toInt().toShort())
+        }
+        eq.enabled = true
+    }
+
+    private fun applyNormalization(sessionId: Int, settings: org.json.JSONObject) {
+        val enabled = settings.optBoolean("normalizeVolume", false)
+
+        if (!enabled) {
+            loudnessEnhancer?.enabled = false
+            return
+        }
+
+        val enhancer = loudnessEnhancer
+            ?: android.media.audiofx.LoudnessEnhancer(sessionId).also { loudnessEnhancer = it }
+
+        // Approximate parity with the Linux dynaudnorm path: LoudnessEnhancer is
+        // a gain stage, not a true EBU R128 normalizer, so these are relative
+        // offsets preserving the Loud > Normal > Quiet ordering.
+        val targetGainMb = when (settings.optString("volumeLevel", "normal")) {
+            "loud" -> 600
+            "quiet" -> -600
+            else -> 0
+        }
+        enhancer.setTargetGain(targetGainMb)
+        enhancer.enabled = true
+    }
+
+    private fun releaseAudioEffects() {
+        try {
+            equalizer?.release()
+        } catch (e: Exception) {
+            android.util.Log.w("JellyTauPlayer", "Equalizer release failed", e)
+        }
+        try {
+            loudnessEnhancer?.release()
+        } catch (e: Exception) {
+            android.util.Log.w("JellyTauPlayer", "LoudnessEnhancer release failed", e)
+        }
+        equalizer = null
+        loudnessEnhancer = null
+    }
+
     /**
      * Get the current playback position in seconds.
      */
@@ -756,6 +947,7 @@ class JellyTauPlayer(private val appContext: Context) {
         mainHandler.post {
             stopPositionUpdates()
             coroutineScope.cancel()
+            releaseAudioEffects()
             exoPlayer.release()
             instance = null
         }

src-tauri/src/commands/player/mod.rs

@@ -57,18 +57,6 @@ pub struct MediaSessionManagerWrapper(pub Mutex<MediaSessionManager>);
 /// @req: DR-048 - Video settings (auto-play toggle, countdown duration)
 pub struct VideoSettingsWrapper(pub Mutex<VideoSettings>);
 
-/// Base offset (seconds) for the active background-audio handoff.
-///
-/// The audio-only stream is requested with `StartTimeTicks` = the handoff
-/// position, so the server makes that point the stream's zero. ExoPlayer then
-/// reports position RELATIVE to that zero. To convert back to an absolute
-/// position on exit (so the video resumes where the audio actually reached), we
-/// add this stored base to the native player's reported position.
-///
-/// TRACES: UR-040 | DR-052
-#[derive(Default)]
-pub struct BackgroundAudioOffset(pub Mutex<f64>);
-
 /// Response for player state queries
 #[derive(specta::Type, Debug, Serialize)]
 #[serde(rename_all = "camelCase")]
@@ -586,7 +574,6 @@ pub async fn player_play_item(
 pub async fn player_enter_background_audio(
     player: State<'_, PlayerStateWrapper>,
     session: State<'_, MediaSessionManagerWrapper>,
-    bg_offset: State<'_, BackgroundAudioOffset>,
     item: PlayItemRequest,
     position_seconds: f64,
 ) -> Result<PlayerStatus, String> {
@@ -636,17 +623,18 @@ pub async fn player_enter_background_audio(
         session_mgr.start_audio_session(media_item.clone());
     }
 
-    // Remember where the video was: the audio stream's zero == this position
-    // (the URL was built with StartTimeTicks=position_seconds), so on exit we add
-    // this base to the native player's relative position to get the absolute one.
-    *bg_offset.0.lock().map_err(|e| e.to_string())? = position_seconds.max(0.0);
-
     // Same base offset drives the lockscreen scrubber: ExoPlayer reports position
     // relative to the stream's StartTimeTicks zero, but the metadata duration is
     // absolute, so shift the reported position back to absolute for the scrubber.
     let _ = crate::player::set_lockscreen_position_offset(position_seconds.max(0.0));
 
     let controller = player.0.lock().await;
+    // Remember where the video was: the audio stream's zero == this position
+    // (the URL was built with StartTimeTicks=position_seconds), so on exit we add
+    // this base to the native player's relative position to get the absolute one.
+    // The controller owns it so a backend-driven advance to the next episode
+    // clears it along with the stream it described.
+    controller.set_background_audio_base(position_seconds);
     controller
         .play_item(media_item)
         .map_err(|e| e.to_string())?;
@@ -677,21 +665,15 @@ pub async fn player_enter_background_audio(
 #[specta::specta]
 pub async fn player_exit_background_audio(
     player: State<'_, PlayerStateWrapper>,
-    bg_offset: State<'_, BackgroundAudioOffset>,
 ) -> Result<f64, String> {
-    // The base offset (handoff position) + native player's relative position =
-    // the absolute position to resume the video at. Read/reset the base first.
-    let base = {
-        let mut off = bg_offset.0.lock().map_err(|e| e.to_string())?;
-        let b = *off;
-        *off = 0.0;
-        b
-    };
-
     // Back to foreground playback: the lockscreen scrubber is absolute again.
     let _ = crate::player::set_lockscreen_position_offset(0.0);
 
     let controller = player.0.lock().await;
+    // The base offset (handoff position) + native player's relative position =
+    // the absolute position to resume the video at. Zero after a backend-driven
+    // episode advance, whose stream already starts at its own zero.
+    let base = controller.take_background_audio_base();
     // Capture position into a `let` BEFORE stop() — never hold work across a lock
     // re-entrant call (deadlock discipline, CLAUDE.md).
     let relative = controller.position();

src-tauri/src/commands/player/timers.rs

@@ -141,6 +141,8 @@ pub async fn player_play_next_episode(
 /// - Frontend when HTML5 video ends (Linux/desktop) - passes itemId + repositoryHandle for the video
 /// - Frontend when audio track ends via backend event - no itemId/repositoryHandle needed
 /// - Android JNI callback also triggers this logic directly
+///
+/// TRACES: UR-023, UR-026, UR-040 | DR-047, DR-052
 #[tauri::command]
 #[specta::specta]
 pub async fn player_on_playback_ended(
@@ -242,12 +244,17 @@ pub async fn player_on_playback_ended(
                 });
             }
 
-            // Start countdown if auto_advance enabled
+            // Advance if auto_advance is enabled. This is the path that actually
+            // runs on Android: the JNI callback's own decision is swallowed by the
+            // NewTrackLoaded end reason set at load, so it returns Stop, emits
+            // PlaybackEnded, and the frontend echoes it back into this command —
+            // which is where the real decision lands.
             if auto_advance {
                 controller_arc
                     .lock()
                     .await
-                    .start_autoplay_countdown(next_episode, countdown_seconds);
+                    .auto_advance_to_next_episode(next_episode, countdown_seconds)
+                    .await;
             }
         }
     }

src-tauri/src/commands/repository.rs

@@ -395,7 +395,12 @@ pub struct SearchUpdateEvent {
     pub result: SearchResult,
 }
 
-/// Search for items
+/// Search for items.
+///
+/// Resolves `SearchOptions::scope` into concrete Jellyfin item types before
+/// dispatching, so scope taxonomy stays in Rust.
+///
+/// TRACES: UR-049, UR-050 | DR-063
 #[tauri::command]
 #[specta::specta]
 pub async fn repository_search(
@@ -408,6 +413,16 @@ pub async fn repository_search(
 ) -> Result<SearchResult, String> {
     let repo = manager.0.get(&handle).ok_or("Repository not found")?;
 
+    // Expand the opaque scope into item types HERE — once, before the cache and
+    // server paths diverge — so both phases filter identically. Doing it later
+    // (or in only one path) makes offline results disagree with online ones.
+    // The frontend sends `scope` and never names a Jellyfin item type for
+    // search; see docs/specs/scoped-search-boundary.md.
+    let options = options.map(|mut o| {
+        o.resolve_scope();
+        o
+    });
+
     // Phase 1: instant local results from the cache (downloaded content) so the
     // UI can render immediately while the server is still being queried.
     let mut cache_result = repo

src-tauri/src/lib.rs

@@ -1196,9 +1196,6 @@ pub fn run() {
             let video_settings = VideoSettingsWrapper(Mutex::new(VideoSettings::default()));
             app.manage(video_settings);
 
-            // Background-audio handoff base offset (UR-040).
-            app.manage(commands::player::BackgroundAudioOffset::default());
-
             // Initialize thumbnail cache
             info!("[INIT] Initializing thumbnail cache...");
             let app_data_dir = if let Ok(test_data_dir) = std::env::var("JELLYTAU_DATA_DIR") {

src-tauri/src/player/android/mod.rs

@@ -18,6 +18,7 @@ use super::events::{PlayerStatusEvent, SharedEventEmitter};
 use super::media::{MediaItem, MediaType};
 use super::state::PlayerState;
 use crate::playback_reporting::{EventThrottler, PlaybackOperation, PlaybackReporter};
+use crate::settings::{audio_settings_jni_payload, AudioSettings};
 use crate::utils::conversions::seconds_to_ticks;
 
 /// Global reference to the JavaVM for JNI callbacks
@@ -148,6 +149,10 @@ struct ExoPlayerState {
     volume: f32,
     is_loaded: bool,
     current_media: Option<MediaItem>,
+    /// Last applied audio settings. Unlike the fields above (which JNI callbacks
+    /// push *in*), this is commanded *out* — audio settings are never reported
+    /// by the player, so this is the authoritative copy for `audio_settings()`.
+    audio_settings: AudioSettings,
 }
 
 impl ExoPlayerState {
@@ -159,6 +164,7 @@ impl ExoPlayerState {
             volume: 1.0,
             is_loaded: false,
             current_media: None,
+            audio_settings: AudioSettings::default(),
         }
     }
 }
@@ -529,6 +535,56 @@ impl PlayerBackend for ExoPlayerBackend {
         self.shared_state.lock_safe().volume
     }
 
+    /// Apply audio settings to ExoPlayer (equalizer, normalization, gapless).
+    ///
+    /// Sent as JSON rather than a wide JNI signature so new fields do not change
+    /// the method signature — the same approach `load()` uses for subtitles. The
+    /// Kotlin side owns the *mechanics* (attaching AudioEffects to the audio
+    /// session); the canonical band layout and preset curves stay in Rust.
+    ///
+    /// TRACES: UR-027, UR-032, UR-033 | DR-030, DR-035, DR-036
+    fn set_audio_settings(&mut self, settings: &AudioSettings) -> Result<(), PlayerError> {
+        let json = audio_settings_jni_payload(settings).map_err(|e| {
+            PlayerError::playback_failed(format!("Failed to serialize audio settings: {}", e))
+        })?;
+
+        let vm = JAVA_VM
+            .get()
+            .ok_or_else(|| PlayerError::playback_failed("JavaVM not initialized"))?;
+
+        let mut env = vm
+            .attach_current_thread()
+            .map_err(|e| PlayerError::playback_failed(format!("Failed to attach thread: {}", e)))?;
+
+        let json_jstring = env.new_string(&json).map_err(|e| {
+            PlayerError::playback_failed(format!("Failed to create settings string: {}", e))
+        })?;
+
+        env.call_method(
+            &self.player_ref,
+            "setAudioSettings",
+            "(Ljava/lang/String;)V",
+            &[JValue::Object(&json_jstring)],
+        )
+        .map_err(|e| {
+            PlayerError::playback_failed(format!("Failed to call setAudioSettings: {}", e))
+        })?;
+
+        // Store the sanitised form so audio_settings() reflects what was applied,
+        // not what was requested.
+        self.shared_state.lock_safe().audio_settings = settings
+            .clone()
+            .with_crossfade_clamped()
+            .with_equalizer_normalised();
+
+        Ok(())
+    }
+
+    /// TRACES: UR-027, UR-032, UR-033 | DR-030, DR-035, DR-036
+    fn audio_settings(&self) -> AudioSettings {
+        self.shared_state.lock_safe().audio_settings.clone()
+    }
+
     fn set_audio_track(&mut self, stream_index: i32) -> Result<(), PlayerError> {
         let vm = JAVA_VM
             .get()
@@ -859,39 +915,19 @@ pub extern "system" fn Java_com_dtourolle_jellytau_player_JellyTauPlayer_nativeO
                     }
 
                     if auto_advance {
-                        // Background audio-only episode: the frontend that normally
-                        // performs the advance (goto /player/<id>) is suspended, so
-                        // the backend must load the next episode's audio-only stream
-                        // itself — otherwise playback just stops at the boundary.
-                        let is_bg_audio_episode =
-                            controller.lock().await.current_is_audio_episode();
-                        if is_bg_audio_episode {
-                            log::info!(
-                                "[Autoplay] Background audio episode — advancing to {} in backend",
-                                next_episode.id
-                            );
-                            let ctrl = controller.lock().await;
-                            if let Err(e) = ctrl
-                                .advance_to_next_episode_audio_only(&next_episode.id)
-                                .await
-                            {
-                                log::error!(
-                                    "[Autoplay] Background audio advance failed: {} — stopping",
-                                    e
-                                );
-                                if let Some(emitter) = EVENT_EMITTER.get() {
-                                    emitter.emit(PlayerStatusEvent::PlaybackEnded);
-                                }
-                            } else {
-                                ctrl.emit_queue_changed();
-                            }
-                        } else {
-                            // Foreground: frontend drives the advance off the countdown.
-                            controller
-                                .lock()
-                                .await
-                                .start_autoplay_countdown(next_episode, countdown_seconds);
-                        }
+                        // Shared with the frontend-invoked command path
+                        // (player_on_playback_ended) so the two dispatchers cannot
+                        // disagree about how a background audio-only episode
+                        // advances — they did, and the command's copy was missing
+                        // the case entirely. That copy is the one that actually
+                        // decides here: the end reason set at load makes this
+                        // callback's own decision Stop, and the frontend echoes the
+                        // resulting PlaybackEnded back into the command.
+                        controller
+                            .lock()
+                            .await
+                            .auto_advance_to_next_episode(next_episode, countdown_seconds)
+                            .await;
                     }
                 }
                 Err(e) => {

src-tauri/src/player/mod.rs

@@ -105,7 +105,7 @@ pub fn set_lockscreen_position_offset(_offset_seconds: f64) -> Result<(), String
 }
 
 use crate::utils::lock::MutexSafe;
-use log::{debug, error, warn};
+use log::{debug, error, info, warn};
 use std::sync::{Arc, Mutex};
 use std::time::Duration;
 use tokio::sync::Mutex as TokioMutex;
@@ -152,6 +152,32 @@ pub struct PlayerController {
 
     // Auto-play episode counter (session-based, resets on manual play)
     autoplay_episode_count: Arc<Mutex<u32>>,
+
+    // Base offset (seconds) of the active background-audio handoff.
+    //
+    // The audio-only stream is requested with `StartTimeTicks` = the position the
+    // video was handed off at, so the server makes that point the stream's zero
+    // and the native player reports position RELATIVE to it. Adding this base back
+    // yields the absolute position to resume the video at on the way out.
+    //
+    // Lives on the controller (not beside the command) because the queue and this
+    // offset describe the same stream: whenever the controller loads a different
+    // one — notably the backend-driven advance to the next episode — the base has
+    // to move with it.
+    //
+    // TRACES: UR-040 | DR-052
+    background_audio_base: Arc<Mutex<f64>>,
+
+    // Last state reported by a webview-rendered HTML5 <video>/<audio> element.
+    //
+    // Webview-rendered media is played by an element the native backend cannot
+    // reach, so the backend's own state() says nothing about it. Tracking the
+    // REPORTED state here is what lets transport (play/pause/toggle) be decided
+    // in Rust for that media instead of the frontend reading `el.paused` off the
+    // DOM — a value that flips transiently while buffering/seeking and caused
+    // competing intents to take opposing actions. `None` means no webview media
+    // is active and the native backend is authoritative. See DR-097.
+    html5_playing: Arc<Mutex<Option<bool>>>,
 }
 
 impl PlayerController {
@@ -174,6 +200,8 @@ impl PlayerController {
             position_throttler,
             end_reason: Arc::new(Mutex::new(None)),
             autoplay_episode_count: Arc::new(Mutex::new(0)),
+            background_audio_base: Arc::new(Mutex::new(0.0)),
+            html5_playing: Arc::new(Mutex::new(None)),
         };
 
         // Start background timer thread for sleep timer countdown
@@ -243,6 +271,23 @@ impl PlayerController {
         self.end_reason.lock_safe().take()
     }
 
+    /// Record that playback is being stopped by an expiring sleep timer.
+    ///
+    /// Stopping the backend makes it fire its ended callback (ExoPlayer does on
+    /// Android), which lands in `on_playback_ended`. Without an end reason that
+    /// reads as a natural finish and autoplay advances — defeating the timer.
+    /// `UserStop` is the honest label: the stop was user-initiated, just via the
+    /// timer they set rather than the stop button.
+    ///
+    /// Takes the shared slot rather than `&self` so the sleep-timer thread —
+    /// which owns clones, not the controller — records it the same way.
+    ///
+    /// TRACES: UR-023, UR-026 | DR-029
+    fn note_sleep_timer_stop(end_reason: &Arc<Mutex<Option<EndReason>>>) {
+        log::debug!("[PlayerController] Sleep timer stop: marking end reason UserStop");
+        *end_reason.lock_safe() = Some(EndReason::UserStop);
+    }
+
     /// Increment autoplay episode counter. Returns true if limit is reached.
     fn increment_autoplay_count(&self) -> bool {
         let max = self.autoplay_settings.lock_safe().max_episodes;
@@ -459,21 +504,72 @@ impl PlayerController {
         Ok(())
     }
 
+    /// True while webview-rendered media (HTML5 `<video>`/`<audio>`) is the real
+    /// player, so transport must be routed to it rather than the native backend.
+    ///
+    /// TRACES: UR-005 | DR-097
+    pub fn is_html5_active(&self) -> bool {
+        self.html5_playing.lock_safe().is_some()
+    }
+
+    /// Whether the webview element last reported itself as playing. Meaningless
+    /// unless [`Self::is_html5_active`] is true.
+    ///
+    /// TRACES: UR-005 | DR-097
+    pub fn html5_is_playing(&self) -> bool {
+        self.html5_playing.lock_safe().unwrap_or(false)
+    }
+
+    /// Send a transport intent to the webview element that is rendering media.
+    fn emit_html5_control(&self, action: &str) {
+        if let Some(emitter) = self.event_emitter.lock_safe().as_ref() {
+            emitter.emit(PlayerStatusEvent::ControlCommand {
+                action: action.to_string(),
+                position: None,
+            });
+        }
+    }
+
     /// Play/resume playback
     pub fn play(&self) -> Result<(), PlayerError> {
         debug!("[PlayerController] play");
+        // Webview-rendered media: the native backend isn't playing it, so drive
+        // the element via a ControlCommand instead (DR-097).
+        if self.is_html5_active() {
+            self.emit_html5_control("play");
+            return Ok(());
+        }
         let mut backend = self.backend.lock_safe();
         backend.play()
     }
 
     /// Pause playback
     pub fn pause(&self) -> Result<(), PlayerError> {
+        if self.is_html5_active() {
+            self.emit_html5_control("pause");
+            return Ok(());
+        }
         let mut backend = self.backend.lock_safe();
         backend.pause()
     }
 
-    /// Toggle play/pause
+    /// Toggle play/pause.
+    ///
+    /// The decision is made HERE, from authoritative state — the reported webview
+    /// state for HTML5-rendered media, or the native backend's state otherwise.
+    /// The frontend must never decide this from the DOM (see DR-097).
+    ///
+    /// TRACES: UR-005 | DR-097
     pub fn toggle_playback(&self) -> Result<(), PlayerError> {
+        if self.is_html5_active() {
+            let action = if self.html5_is_playing() {
+                "pause"
+            } else {
+                "play"
+            };
+            self.emit_html5_control(action);
+            return Ok(());
+        }
         let mut backend = self.backend.lock_safe();
         if backend.state().is_playing() {
             backend.pause()
@@ -767,6 +863,7 @@ impl PlayerController {
         let sleep_timer = self.sleep_timer.clone();
         let event_emitter = self.event_emitter.clone();
         let backend = self.backend.clone();
+        let end_reason = self.end_reason.clone();
 
         std::thread::spawn(move || {
             loop {
@@ -783,6 +880,14 @@ impl PlayerController {
                         debug!("[SleepTimer] Time-based timer expired, stopping playback");
                         timer.cancel();
 
+                        // Mark the stop *before* it reaches the backend. Stopping
+                        // makes the native player fire its ended callback, and
+                        // cancelling the timer above means on_playback_ended can no
+                        // longer tell this apart from a natural end — without this
+                        // it would show the next-episode popup / autoplay right
+                        // after the sleep timer fired.
+                        Self::note_sleep_timer_stop(&end_reason);
+
                         // Emit cancelled state
                         if let Some(emitter) = event_emitter.lock_safe().as_ref() {
                             emitter.emit(PlayerStatusEvent::SleepTimerChanged {
@@ -864,6 +969,23 @@ impl PlayerController {
     /// Re-emits a `StateChanged` event identical to what MpvBackend/ExoPlayer
     /// would emit, so `playerEvents.ts` needs no HTML5-specific branch.
     pub fn report_html5_state(&self, state: String, media_id: Option<String>) {
+        // Track it: this is the authoritative play/pause state for
+        // webview-rendered media, and what transport decisions read (DR-097).
+        // "stopped"/"idle" mean the element is gone, so hand authority back to
+        // the native backend — otherwise music playback would keep emitting
+        // ControlCommands at a element that no longer exists.
+        {
+            let mut tracked = self.html5_playing.lock_safe();
+            *tracked = match state.as_str() {
+                "playing" => Some(true),
+                // "loading" counts as active-but-not-playing so a toggle during
+                // load resolves to "play" rather than falling through to the
+                // native backend.
+                "paused" | "loading" => Some(false),
+                // "stopped"/"idle": element is gone, native backend resumes authority.
+                _ => None,
+            };
+        }
         if let Some(emitter) = self.event_emitter.lock_safe().as_ref() {
             emitter.emit(PlayerStatusEvent::StateChanged { state, media_id });
         }
@@ -1064,6 +1186,68 @@ impl PlayerController {
         }
     }
 
+    /// Record the base offset of a background-audio handoff (the position the
+    /// video was handed off at, which is the audio stream's zero).
+    ///
+    /// TRACES: UR-040 | DR-052
+    pub fn set_background_audio_base(&self, seconds: f64) {
+        *self.background_audio_base.lock_safe() = seconds.max(0.0);
+    }
+
+    /// Read and clear the background-audio base offset.
+    ///
+    /// TRACES: UR-040 | DR-052
+    pub fn take_background_audio_base(&self) -> f64 {
+        let mut base = self.background_audio_base.lock_safe();
+        std::mem::replace(&mut *base, 0.0)
+    }
+
+    /// Perform the auto-advance for a `ShowNextEpisodePopup` decision.
+    ///
+    /// Single place both end-of-playback dispatchers agree on: the Android JNI
+    /// callback (`nativeOnPlaybackEnded`) and the frontend-invoked command
+    /// (`player_on_playback_ended`). They used to each carry their own copy of
+    /// this branch, and the command's copy was missing the background-audio case
+    /// entirely — so an audio-only episode ending while backgrounded only ever
+    /// started a countdown that nothing could act on.
+    ///
+    /// TRACES: UR-040, UR-023 | DR-052
+    pub async fn auto_advance_to_next_episode(
+        &self,
+        next_episode: crate::repository::types::MediaItem,
+        countdown_seconds: u32,
+    ) {
+        // Background audio-only episode: the countdown only emits ticks — the
+        // advance itself is a `goto('/player/<id>')` in the webview, which cannot
+        // start audio while the app is backgrounded. Load the next episode's
+        // audio-only stream here instead, or playback stalls at the boundary.
+        if self.current_is_audio_episode() {
+            info!(
+                "[PlayerController] Background audio episode — advancing to {} in backend",
+                next_episode.id
+            );
+            match self
+                .advance_to_next_episode_audio_only(&next_episode.id)
+                .await
+            {
+                Ok(()) => self.emit_queue_changed(),
+                Err(e) => {
+                    error!(
+                        "[PlayerController] Background audio advance failed: {} — stopping",
+                        e
+                    );
+                    if let Some(emitter) = self.event_emitter() {
+                        emitter.emit(PlayerStatusEvent::PlaybackEnded);
+                    }
+                }
+            }
+            return;
+        }
+
+        // Foreground: the frontend drives the advance off the countdown ticks.
+        self.start_autoplay_countdown(next_episode, countdown_seconds);
+    }
+
     /// Advance to the next episode while playing audio-only in the background.
     ///
     /// The normal autoplay-next path navigates the frontend to `/player/<id>`,
@@ -1074,10 +1258,10 @@ impl PlayerController {
     ///
     /// `next_episode_id` is the Jellyfin item ID of the episode to play next.
     ///
-    /// Called from the Android autoplay dispatch (`#[cfg(android)]`); compiled and
-    /// unit-tested on the host, hence `allow(dead_code)` off-Android.
+    /// Reached through `auto_advance_to_next_episode`, which gates it on
+    /// `current_is_audio_episode()` — only ever true after a background-audio
+    /// handoff (Android), but compiled and unit-tested on every platform.
     /// TRACES: UR-040, UR-023 | DR-052
-    #[cfg_attr(not(target_os = "android"), allow(dead_code))]
     pub async fn advance_to_next_episode_audio_only(
         &self,
         next_episode_id: &str,
@@ -1132,6 +1316,13 @@ impl PlayerController {
             server_id: Some(next.server_id.clone()),
         };
 
+        // The previous episode's handoff base described the stream we are leaving.
+        // This one is built without StartTimeTicks, so its timeline is already
+        // absolute: clear the base (used to resolve the resume position on the way
+        // back to the foreground) and the lockscreen scrubber's matching shift.
+        self.set_background_audio_base(0.0);
+        let _ = set_lockscreen_position_offset(0.0);
+
         self.play_item(media_item).map_err(|e| e.to_string())
     }
 
@@ -1463,6 +1654,156 @@ mod tests {
         }
     }
 
+    // ===== HTML5 transport authority (DR-097) =====
+    //
+    // Webview-rendered video is played by an element the native backend cannot
+    // reach, so transport for it must be decided from the state the element
+    // REPORTS and executed by emitting a ControlCommand. Previously the frontend
+    // decided play-vs-pause itself by reading `el.paused` off the DOM, which
+    // flips transiently while buffering/seeking — two intents ~150ms apart read
+    // different values, took opposing actions, and self-sustained a pause loop.
+
+    #[test]
+    fn test_html5_state_is_tracked_from_reports() {
+        let controller = PlayerController::default();
+        let emitter = Arc::new(CapturingEmitter::new());
+        controller.set_event_emitter(emitter.clone());
+
+        // No HTML5 media reported yet: the native backend stays authoritative.
+        assert!(!controller.is_html5_active());
+
+        controller.report_html5_state("playing".to_string(), Some("item-1".to_string()));
+        assert!(controller.is_html5_active());
+        assert!(controller.html5_is_playing());
+
+        controller.report_html5_state("paused".to_string(), Some("item-1".to_string()));
+        assert!(controller.is_html5_active());
+        assert!(!controller.html5_is_playing());
+    }
+
+    #[test]
+    fn test_html5_toggle_from_paused_emits_play_control() {
+        let controller = PlayerController::default();
+        let emitter = Arc::new(CapturingEmitter::new());
+        controller.set_event_emitter(emitter.clone());
+        controller.report_html5_state("paused".to_string(), Some("item-1".to_string()));
+
+        controller.toggle_playback().unwrap();
+
+        let controls: Vec<_> = emitter
+            .events()
+            .into_iter()
+            .filter_map(|e| match e {
+                PlayerStatusEvent::ControlCommand { action, .. } => Some(action),
+                _ => None,
+            })
+            .collect();
+        assert_eq!(controls, vec!["play".to_string()]);
+    }
+
+    #[test]
+    fn test_html5_toggle_from_playing_emits_pause_control() {
+        let controller = PlayerController::default();
+        let emitter = Arc::new(CapturingEmitter::new());
+        controller.set_event_emitter(emitter.clone());
+        controller.report_html5_state("playing".to_string(), Some("item-1".to_string()));
+
+        controller.toggle_playback().unwrap();
+
+        let controls: Vec<_> = emitter
+            .events()
+            .into_iter()
+            .filter_map(|e| match e {
+                PlayerStatusEvent::ControlCommand { action, .. } => Some(action),
+                _ => None,
+            })
+            .collect();
+        assert_eq!(controls, vec!["pause".to_string()]);
+    }
+
+    #[test]
+    fn test_html5_repeated_toggles_alternate_and_never_repeat_an_action() {
+        // The loop signature: two intents in quick succession must NOT both
+        // resolve the same way, and must not produce opposing actions from a
+        // stale read. Rust's own tracked state makes the sequence deterministic
+        // as long as the element reports back between intents.
+        let controller = PlayerController::default();
+        let emitter = Arc::new(CapturingEmitter::new());
+        controller.set_event_emitter(emitter.clone());
+        controller.report_html5_state("playing".to_string(), Some("item-1".to_string()));
+
+        controller.toggle_playback().unwrap();
+        // Element confirms the pause it was told to do.
+        controller.report_html5_state("paused".to_string(), Some("item-1".to_string()));
+        controller.toggle_playback().unwrap();
+
+        let controls: Vec<_> = emitter
+            .events()
+            .into_iter()
+            .filter_map(|e| match e {
+                PlayerStatusEvent::ControlCommand { action, .. } => Some(action),
+                _ => None,
+            })
+            .collect();
+        assert_eq!(controls, vec!["pause".to_string(), "play".to_string()]);
+    }
+
+    #[test]
+    fn test_html5_play_and_pause_emit_control_commands() {
+        let controller = PlayerController::default();
+        let emitter = Arc::new(CapturingEmitter::new());
+        controller.set_event_emitter(emitter.clone());
+        controller.report_html5_state("paused".to_string(), Some("item-1".to_string()));
+
+        controller.play().unwrap();
+        controller.pause().unwrap();
+
+        let controls: Vec<_> = emitter
+            .events()
+            .into_iter()
+            .filter_map(|e| match e {
+                PlayerStatusEvent::ControlCommand { action, .. } => Some(action),
+                _ => None,
+            })
+            .collect();
+        assert_eq!(controls, vec!["play".to_string(), "pause".to_string()]);
+    }
+
+    #[test]
+    fn test_html5_stopped_report_releases_transport_to_native_backend() {
+        // When webview video goes away, transport must fall back to the native
+        // backend (music playback must not keep emitting ControlCommands).
+        let controller = PlayerController::default();
+        let emitter = Arc::new(CapturingEmitter::new());
+        controller.set_event_emitter(emitter.clone());
+
+        controller.report_html5_state("playing".to_string(), Some("item-1".to_string()));
+        assert!(controller.is_html5_active());
+
+        controller.report_html5_state("stopped".to_string(), None);
+        assert!(!controller.is_html5_active());
+    }
+
+    #[test]
+    fn test_html5_transport_emits_exactly_one_control_per_intent() {
+        // Guards against a double-drive on platforms where the *backend* is also
+        // webview-based (WebviewAudioBackend on Windows): the html5 short-circuit
+        // must replace the backend call, not run in addition to it.
+        let controller = PlayerController::default();
+        let emitter = Arc::new(CapturingEmitter::new());
+        controller.set_event_emitter(emitter.clone());
+        controller.report_html5_state("playing".to_string(), Some("item-1".to_string()));
+
+        controller.pause().unwrap();
+
+        let controls = emitter
+            .events()
+            .into_iter()
+            .filter(|e| matches!(e, PlayerStatusEvent::ControlCommand { .. }))
+            .count();
+        assert_eq!(controls, 1, "one intent must produce exactly one control");
+    }
+
     #[test]
     fn test_controller_volume_default() {
         let controller = PlayerController::default();
@@ -2040,6 +2381,51 @@ mod tests {
         }
     }
 
+    /// A time-based sleep timer that fires mid-episode must not let the ended
+    /// callback fall through to autoplay.
+    ///
+    /// The timer thread stops the backend directly, which makes ExoPlayer emit
+    /// its ended callback. That callback races the thread's own `timer.cancel()`:
+    /// by the time `on_playback_ended` inspects the sleep timer it reads `Off`,
+    /// so the timer branch is skipped and the episode path runs — showing a
+    /// next-episode popup (or advancing) after the user's sleep timer expired.
+    #[tokio::test]
+    async fn test_expired_time_sleep_timer_stops_without_autoplay() {
+        let controller = PlayerController::default();
+
+        let items = create_test_items(3);
+        controller.play_queue(items, 0).unwrap();
+        controller.take_end_reason();
+
+        // Arm a time-based timer that is already due, then let the real timer
+        // thread (started in the constructor, 1s tick) observe the expiry and
+        // run its stop path. Driving the actual thread is the point: the bug was
+        // that this path stopped the backend without recording an end reason.
+        let now = chrono::Utc::now().timestamp_millis();
+        controller.set_sleep_timer(SleepTimerMode::Time { end_time: now });
+
+        // Wait for the timer thread to process the expiry (tick is 1s).
+        for _ in 0..40 {
+            tokio::time::sleep(std::time::Duration::from_millis(100)).await;
+            if !controller.sleep_timer.lock_safe().is_active() {
+                break;
+            }
+        }
+        assert!(
+            !controller.sleep_timer.lock_safe().is_active(),
+            "Timer thread should have expired and cancelled the sleep timer"
+        );
+
+        // The backend stop above makes the native player fire its ended callback.
+        let decision = controller.on_playback_ended().await.unwrap();
+
+        assert!(
+            matches!(decision, AutoplayDecision::Stop),
+            "Expected Stop after an expired time-based sleep timer, got {:?}",
+            decision
+        );
+    }
+
     #[tokio::test]
     async fn test_empty_queue_stops() {
         let controller = PlayerController::default();
@@ -2693,6 +3079,119 @@ mod tests {
         assert!(controller.current_is_audio_episode());
     }
 
+    /// The handoff base offset describes ONE stream: the audio-only URL built
+    /// with `StartTimeTicks` = the position the video was handed off at, whose
+    /// timeline therefore starts at that point. The next episode is loaded from
+    /// its own beginning, so its timeline is already absolute and the base must
+    /// be cleared — otherwise returning to the foreground resolves the resume
+    /// position as `old_base + position_in_new_episode` and the video jumps to a
+    /// point that has nothing to do with what was playing.
+    #[tokio::test]
+    async fn test_advance_to_next_episode_audio_only_clears_handoff_base() {
+        let controller = PlayerController::default();
+        controller.set_repository(Arc::new(MockEpisodeRepo::season(3)));
+
+        // Handed off 20 minutes into the previous episode.
+        controller.set_background_audio_base(1200.0);
+
+        controller
+            .advance_to_next_episode_audio_only("ep2")
+            .await
+            .expect("advance should succeed");
+
+        assert_eq!(
+            controller.take_background_audio_base(),
+            0.0,
+            "the next episode starts at its own zero, so the previous handoff \
+             base must not survive the advance"
+        );
+    }
+
+    /// A background audio-only episode must advance IN THE BACKEND when the
+    /// autoplay decision comes back as ShowNextEpisodePopup — never by starting a
+    /// countdown the frontend is supposed to act on.
+    ///
+    /// The countdown only emits CountdownTick events; the actual advance is a
+    /// `goto('/player/<id>')` in the webview. While the app is backgrounded that
+    /// navigation cannot start audio, so playback stalls at the episode boundary
+    /// with ExoPlayer parked in STATE_ENDED — and any later play intent
+    /// (lockscreen, headset, Bluetooth reconnect) replays the ended item from the
+    /// start, which is what surfaces to the user as "the episode randomly
+    /// restarted".
+    #[tokio::test]
+    async fn test_auto_advance_background_audio_episode_advances_in_backend() {
+        let controller = PlayerController::default();
+        controller.set_repository(Arc::new(MockEpisodeRepo::season(3)));
+
+        // Currently playing: ep2 handed off to audio-only background playback.
+        let episode = MediaItem {
+            id: "ep2".to_string(),
+            item_type: Some("Episode".to_string()),
+            media_type: MediaType::Audio,
+            series_id: Some("series1".to_string()),
+            source: MediaSource::Remote {
+                stream_url: "http://example.com/ep2-audio.mp3".to_string(),
+                jellyfin_item_id: "ep2".to_string(),
+            },
+            ..create_test_items(1).remove(0)
+        };
+        controller.play_queue(vec![episode], 0).unwrap();
+
+        let next = make_repo_episode("ep3", 3);
+        controller.auto_advance_to_next_episode(next, 10).await;
+
+        let current = controller
+            .queue
+            .lock_safe()
+            .current()
+            .cloned()
+            .expect("an item should still be loaded");
+        assert_eq!(
+            current.id, "ep3",
+            "background audio-only episode must advance in the backend, not wait \
+             for a frontend navigation that cannot happen while backgrounded"
+        );
+        assert_eq!(current.media_type, MediaType::Audio);
+        assert!(controller.current_is_audio_episode());
+    }
+
+    /// Foreground video playback keeps the countdown-driven advance: the frontend
+    /// owns the navigation there, so the backend must NOT load the next episode
+    /// itself (that would race the page transition and double-start playback).
+    #[tokio::test]
+    async fn test_auto_advance_foreground_video_episode_uses_countdown() {
+        let controller = PlayerController::default();
+        controller.set_repository(Arc::new(MockEpisodeRepo::season(3)));
+
+        let episode = MediaItem {
+            id: "ep2".to_string(),
+            item_type: Some("Episode".to_string()),
+            media_type: MediaType::Video,
+            series_id: Some("series1".to_string()),
+            source: MediaSource::Remote {
+                stream_url: "http://example.com/ep2.m3u8".to_string(),
+                jellyfin_item_id: "ep2".to_string(),
+            },
+            ..create_test_items(1).remove(0)
+        };
+        controller.play_queue(vec![episode], 0).unwrap();
+
+        let next = make_repo_episode("ep3", 3);
+        controller.auto_advance_to_next_episode(next, 10).await;
+
+        let current = controller
+            .queue
+            .lock_safe()
+            .current()
+            .cloned()
+            .expect("an item should still be loaded");
+        assert_eq!(
+            current.id, "ep2",
+            "foreground video advance is frontend-driven; the backend must not \
+             swap the queue item out from under it"
+        );
+    }
+
     /// Without a controller repository the Android episode path must still
     /// stop gracefully (previous behavior) rather than error.
     #[tokio::test]

src-tauri/src/repository/types.rs

@@ -294,6 +294,53 @@ pub struct GetItemsOptions {
     pub genres: Option<Vec<String>>,
 }
 
+/// An opaque search scope the frontend selects; Rust owns what it *means*.
+///
+/// The expansion table below is Jellyfin domain vocabulary: it changes when
+/// Jellyfin adds or renames an item type, never when the UI is redesigned. It
+/// previously lived in the frontend (`searchScope.ts`), which is the boundary
+/// leak documented in docs/specs/scoped-search-boundary.md. The frontend now
+/// sends the enum and never names an item type in connection with search.
+///
+/// TRACES: UR-049 | DR-063
+#[derive(specta::Type, Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub enum SearchScope {
+    All,
+    Music,
+    Movies,
+    Tv,
+}
+
+impl SearchScope {
+    /// The Jellyfin item types this scope requests, or `None` for `All`.
+    ///
+    /// `All` returns `None` rather than the union of every listed type on
+    /// purpose: an explicit `includeItemTypes` list filters out anything not
+    /// named in it, so a union would silently drop People, folders and any type
+    /// nobody enumerated. Callers must omit the filter entirely on `None`.
+    ///
+    /// TRACES: UR-049 | DR-063
+    pub fn item_types(self) -> Option<Vec<String>> {
+        match self {
+            SearchScope::All => None,
+            SearchScope::Music => Some(
+                ["MusicAlbum", "MusicArtist", "Audio", "Playlist"]
+                    .into_iter()
+                    .map(String::from)
+                    .collect(),
+            ),
+            SearchScope::Movies => Some(vec!["Movie".to_string()]),
+            SearchScope::Tv => Some(
+                ["Series", "Episode"]
+                    .into_iter()
+                    .map(String::from)
+                    .collect(),
+            ),
+        }
+    }
+}
+
 /// Options for search queries
 #[derive(specta::Type, Debug, Clone, Serialize, Deserialize, Default)]
 #[serde(rename_all = "camelCase")]
@@ -304,6 +351,28 @@ pub struct SearchOptions {
     pub include_item_types: Option<Vec<String>>,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub search_term: Option<String>,
+    /// Opaque scope selected by the UI. When set it **wins** over
+    /// `include_item_types`, which remains for the non-search `get_items`
+    /// callers that legitimately request a single concrete type.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub scope: Option<SearchScope>,
+}
+
+impl SearchOptions {
+    /// Expand `scope` into `include_item_types` in place.
+    ///
+    /// Call this once, in the search command, *before* dispatching to the
+    /// cache and server paths — both already honour `include_item_types`, and
+    /// resolving in one place keeps online and offline results identical.
+    ///
+    /// TRACES: UR-049 | DR-063
+    pub fn resolve_scope(&mut self) {
+        if let Some(scope) = self.scope {
+            // `All` yields None, which clears the filter — the correct
+            // behaviour, not an omission.
+            self.include_item_types = scope.item_types();
+        }
+    }
 }
 
 /// Playback information
@@ -455,6 +524,131 @@ impl MeaningfulContent for PlaylistCreatedResult {
     }
 }
 
+#[cfg(test)]
+mod search_scope_tests {
+    use super::*;
+
+    /// Music expands to the four Jellyfin types that make up the category.
+    ///
+    /// This table is the domain vocabulary that used to live in the frontend
+    /// (`searchScope.ts`'s `SCOPE_ITEM_TYPES`) — the boundary leak that
+    /// docs/specs/scoped-search-boundary.md was written about.
+    ///
+    /// @req-test: UT-089 - SearchScope expands to Jellyfin item types
+    #[test]
+    fn music_scope_expands_to_music_item_types() {
+        assert_eq!(
+            SearchScope::Music.item_types(),
+            Some(vec![
+                "MusicAlbum".to_string(),
+                "MusicArtist".to_string(),
+                "Audio".to_string(),
+                "Playlist".to_string(),
+            ])
+        );
+    }
+
+    /// @req-test: UT-089 - SearchScope expands to Jellyfin item types
+    #[test]
+    fn movies_scope_expands_to_movie_only() {
+        assert_eq!(
+            SearchScope::Movies.item_types(),
+            Some(vec!["Movie".to_string()])
+        );
+    }
+
+    /// @req-test: UT-089 - SearchScope expands to Jellyfin item types
+    #[test]
+    fn tv_scope_expands_to_series_and_episode() {
+        assert_eq!(
+            SearchScope::Tv.item_types(),
+            Some(vec!["Series".to_string(), "Episode".to_string()])
+        );
+    }
+
+    /// `All` must send NO filter — not the union of the other scopes.
+    ///
+    /// Sending a union would silently drop every type nobody enumerated
+    /// (Person, folders, …), which an explicit `includeItemTypes` list filters
+    /// out. This is why `item_types()` returns Option rather than Vec.
+    ///
+    /// @req-test: UT-090 - All scope sends no item-type filter
+    #[test]
+    fn all_scope_sends_no_filter() {
+        assert_eq!(SearchScope::All.item_types(), None);
+    }
+
+    /// Scope wins over an explicitly supplied include_item_types.
+    ///
+    /// @req-test: UT-091 - Scope takes precedence over include_item_types
+    #[test]
+    fn resolve_scope_overrides_include_item_types() {
+        let mut options = SearchOptions {
+            include_item_types: Some(vec!["Movie".to_string()]),
+            scope: Some(SearchScope::Music),
+            ..Default::default()
+        };
+        options.resolve_scope();
+
+        assert_eq!(
+            options.include_item_types,
+            Some(vec![
+                "MusicAlbum".to_string(),
+                "MusicArtist".to_string(),
+                "Audio".to_string(),
+                "Playlist".to_string(),
+            ])
+        );
+    }
+
+    /// `All` clears any include_item_types so no filter reaches the query.
+    ///
+    /// @req-test: UT-090 - All scope sends no item-type filter
+    #[test]
+    fn resolve_all_scope_clears_include_item_types() {
+        let mut options = SearchOptions {
+            include_item_types: Some(vec!["Movie".to_string()]),
+            scope: Some(SearchScope::All),
+            ..Default::default()
+        };
+        options.resolve_scope();
+
+        assert_eq!(options.include_item_types, None);
+    }
+
+    /// With no scope set, include_item_types passes through untouched — the
+    /// non-search `getItems` callers rely on this.
+    ///
+    /// @req-test: UT-091 - Scope takes precedence over include_item_types
+    #[test]
+    fn resolve_without_scope_preserves_include_item_types() {
+        let mut options = SearchOptions {
+            include_item_types: Some(vec!["MusicAlbum".to_string()]),
+            scope: None,
+            ..Default::default()
+        };
+        options.resolve_scope();
+
+        assert_eq!(
+            options.include_item_types,
+            Some(vec!["MusicAlbum".to_string()])
+        );
+    }
+
+    /// The frontend sends the enum as camelCase over IPC.
+    ///
+    /// @req-test: UT-089 - SearchScope expands to Jellyfin item types
+    #[test]
+    fn scope_deserializes_from_camel_case() {
+        let options: SearchOptions =
+            serde_json::from_str(r#"{"scope": "music", "limit": 10}"#).unwrap();
+        assert!(matches!(options.scope, Some(SearchScope::Music)));
+
+        let all: SearchOptions = serde_json::from_str(r#"{"scope": "all"}"#).unwrap();
+        assert!(matches!(all.scope, Some(SearchScope::All)));
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

src-tauri/src/settings.rs

@@ -179,10 +179,80 @@ impl VideoSettings {
     }
 }
 
+/// Serialise `AudioSettings` into the JSON payload handed to the Android player
+/// over JNI.
+///
+/// Sanitises first (crossfade clamped, band vector normalised) so a malformed
+/// vector can never reach the Kotlin parser. JSON is used rather than a wide JNI
+/// signature so that adding a field does not change the method signature — the
+/// same approach `load()` already uses for subtitles.
+///
+/// The emitted keys are camelCase (serde) and `volumeLevel` is lowercase; the
+/// Kotlin side matches on those literals. Both are pinned by tests.
+///
+/// TRACES: UR-027, UR-032, UR-033 | DR-030, DR-035, DR-036
+pub fn audio_settings_jni_payload(settings: &AudioSettings) -> Result<String, serde_json::Error> {
+    let sanitised = settings
+        .clone()
+        .with_crossfade_clamped()
+        .with_equalizer_normalised();
+    serde_json::to_string(&sanitised)
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
 
+    /// The JNI payload must sanitise before serialising: an over-long crossfade
+    /// is clamped and a wrong-length band vector is normalised to EQ_BANDS.len().
+    /// Sending raw values would let a malformed vector reach the Kotlin parser.
+    ///
+    /// TRACES: UR-027, UR-032, UR-033 | DR-030, DR-035, DR-036 | UT-AUDIO-JNI-1
+    #[test]
+    fn test_audio_settings_jni_payload_is_sanitised() {
+        let settings = AudioSettings {
+            crossfade_duration: 30.0,
+            equalizer_bands: vec![20.0, -30.0],
+            ..AudioSettings::default()
+        };
+
+        let json = audio_settings_jni_payload(&settings).expect("serialises");
+        let v: serde_json::Value = serde_json::from_str(&json).expect("valid JSON");
+
+        assert_eq!(v["crossfadeDuration"], 12.0, "crossfade clamped to 12s");
+
+        let bands = v["equalizerBands"].as_array().expect("bands array");
+        assert_eq!(bands.len(), EQ_BANDS.len(), "band vector normalised to 10");
+        assert_eq!(bands[0], EQ_GAIN_MAX as f64, "gain clamped to +12dB");
+        assert_eq!(bands[1], EQ_GAIN_MIN as f64, "gain clamped to -12dB");
+    }
+
+    /// The Kotlin side parses these exact keys. camelCase is what serde emits
+    /// for AudioSettings; a rename here silently breaks the Android parser,
+    /// which is why the contract is pinned by a test rather than by convention.
+    ///
+    /// TRACES: UR-027, UR-032, UR-033 | DR-030, DR-035, DR-036 | UT-AUDIO-JNI-2
+    #[test]
+    fn test_audio_settings_jni_payload_key_contract() {
+        let json = audio_settings_jni_payload(&AudioSettings::default()).expect("serialises");
+        let v: serde_json::Value = serde_json::from_str(&json).expect("valid JSON");
+
+        for key in [
+            "crossfadeDuration",
+            "gaplessPlayback",
+            "normalizeVolume",
+            "volumeLevel",
+            "equalizerEnabled",
+            "equalizerBands",
+        ] {
+            assert!(v.get(key).is_some(), "JNI payload must carry `{key}`");
+        }
+
+        // VolumeLevel is #[serde(rename_all = "lowercase")]; Kotlin matches on
+        // these literals.
+        assert_eq!(v["volumeLevel"], "normal");
+    }
+
     #[test]
     fn test_default_settings() {
         let settings = AudioSettings::default();

src-tauri/tauri.conf.json

@@ -1,7 +1,7 @@
 {
   "$schema": "https://schema.tauri.app/config/2",
   "productName": "jellytau",
-  "version": "0.1.2",
+  "version": "0.2.9",
   "identifier": "com.dtourolle.jellytau",
   "build": {
     "beforeDevCommand": "bun run dev",

src/lib/api/bindings.ts

@@ -237,6 +237,8 @@ async playerPlayNextEpisode(item: PlayItemRequest) : Promise<PlayerStatus> {
  * - Frontend when HTML5 video ends (Linux/desktop) - passes itemId + repositoryHandle for the video
  * - Frontend when audio track ends via backend event - no itemId/repositoryHandle needed
  * - Android JNI callback also triggers this logic directly
+ * 
+ * TRACES: UR-023, UR-026, UR-040 | DR-047, DR-052
  */
 async playerOnPlaybackEnded(itemId: string | null, repositoryHandle: string | null) : Promise<null> {
     return await TAURI_INVOKE("player_on_playback_ended", { itemId, repositoryHandle });
@@ -1290,7 +1292,12 @@ async repositoryGetGenres(handle: string, parentId: string | null) : Promise<Gen
     return await TAURI_INVOKE("repository_get_genres", { handle, parentId });
 },
 /**
- * Search for items
+ * Search for items.
+ * 
+ * Resolves `SearchOptions::scope` into concrete Jellyfin item types before
+ * dispatching, so scope taxonomy stays in Rust.
+ * 
+ * TRACES: UR-049, UR-050 | DR-063
  */
 async repositorySearch(handle: string, query: string, options: SearchOptions | null, requestId: number) : Promise<SearchResult> {
     return await TAURI_INVOKE("repository_search", { handle, query, options, requestId });
@@ -2517,11 +2524,29 @@ failed: number }
 /**
  * Options for search queries
  */
-export type SearchOptions = { limit?: number | null; includeItemTypes?: string[] | null; searchTerm?: string | null }
+export type SearchOptions = { limit?: number | null; includeItemTypes?: string[] | null; searchTerm?: string | null; 
+/**
+ * Opaque scope selected by the UI. When set it **wins** over
+ * `include_item_types`, which remains for the non-search `get_items`
+ * callers that legitimately request a single concrete type.
+ */
+scope?: SearchScope | null }
 /**
  * Search result with pagination
  */
 export type SearchResult = { items: MediaItem[]; totalRecordCount: number }
+/**
+ * An opaque search scope the frontend selects; Rust owns what it *means*.
+ * 
+ * The expansion table below is Jellyfin domain vocabulary: it changes when
+ * Jellyfin adds or renames an item type, never when the UI is redesigned. It
+ * previously lived in the frontend (`searchScope.ts`), which is the boundary
+ * leak documented in docs/specs/scoped-search-boundary.md. The frontend now
+ * sends the enum and never names an item type in connection with search.
+ * 
+ * TRACES: UR-049 | DR-063
+ */
+export type SearchScope = "all" | "music" | "movies" | "tv"
 /**
  * Security status info
  */

src/lib/components/player/VideoPlayer.svelte

@@ -1,4 +1,4 @@
-<!-- TRACES: UR-003, UR-005, UR-020, UR-021, UR-026, UR-040 | DR-010, DR-023, DR-024, DR-051, DR-052 -->
+<!-- TRACES: UR-003, UR-005, UR-020, UR-021, UR-026, UR-040, UR-061 | DR-010, DR-023, DR-024, DR-051, DR-052, DR-092, DR-098, DR-099 -->
 <script lang="ts">
   import { onMount, onDestroy, untrack } from "svelte";
   import { goto } from "$app/navigation";
@@ -20,6 +20,17 @@
   import { Html5PlayerAdapter, type Html5ElementBridge } from "$lib/player/adapters";
   import { createRustReportHost } from "$lib/player/adapters/rustReportHost";
   import { isPipSupported, enterPip, setAutoEnterEnabled } from "$lib/utils/pictureInPicture";
+  import {
+    createTapGestureState,
+    registerTap,
+    resolveSeekTarget,
+    clampSeekTarget,
+    isSynthesizedTouchClick,
+    isControlSurfaceTouch,
+    SEEK_FORWARD_SECONDS,
+    SEEK_BACKWARD_SECONDS,
+    type TapFeedback,
+  } from "./tapGestures";
   import {
     setBackgroundAudioEnabled,
     subscribeAppBackgrounded,
@@ -102,12 +113,25 @@
   let touchStartX = $state(0);
   let touchStartY = $state(0);
   let touchStartTime = $state(0);
-  let lastTapTime = $state(0);
-  let tapTimeout: ReturnType<typeof setTimeout> | null = null;
+  let tapGestures = createTapGestureState();
+  // When a touch tap last ran the gesture handler, so the compatibility click
+  // the browser synthesizes afterwards can be ignored (see handleVideoClick).
+  let lastTouchTapAt = 0;
   let brightness = $state(1); // 0-2, default 1
-  let showDoubleTapFeedback = $state<"left" | "right" | null>(null);
+  let showDoubleTapFeedback = $state<TapFeedback | null>(null);
   let doubleTapFeedbackTimeout: ReturnType<typeof setTimeout> | null = null;
+  // Target of a skip already requested but not yet reported back by the player,
+  // so back-to-back double taps chain instead of stacking on a stale position.
+  let pendingSeekTarget: number | null = null;
   let swipeGestureActive = $state(false);
+  // Whether the in-flight touch belongs to the player surface (and so may be
+  // read as a tap/swipe gesture) rather than to a control. Set on touchstart,
+  // cleared on touchend — see handleTouchMove for why a per-gesture flag and not
+  // just a per-event target check.
+  let playerGestureActive = false;
+  // Raised when the user changes the seek bar's value, cleared by whichever
+  // release signal commits the seek. See handleSeekBarRelease.
+  let seekCommitArmed = false;
 
   // Backend info from Rust (Rust decides which backend to use based on platform)
   let useHtml5Element = $state(true); // Default to HTML5, Rust will override if using native backend
@@ -674,15 +698,19 @@
           bufferedRanges.push(`[${buffered.start(i).toFixed(1)} - ${buffered.end(i).toFixed(1)}]`);
         }
 
-        console.log("[VideoPlayer Debug]", {
-          currentTime: videoElement.currentTime.toFixed(2),
-          displayTime: currentTime.toFixed(2),
-          buffered: bufferedRanges.join(", "),
-          readyState: videoElement.readyState,
-          paused: videoElement.paused,
-          seeking: videoElement.seeking,
-          playbackRate: videoElement.playbackRate,
-        });
+        // Flattened to a single string on purpose: the Android WebView console
+        // bridge stringifies objects as "[object Object]" in logcat, which made
+        // this whole payload useless when diagnosing over adb.
+        console.log(
+          `[VideoPlayer Debug] t=${videoElement.currentTime.toFixed(2)}` +
+            ` display=${currentTime.toFixed(2)}` +
+            ` readyState=${videoElement.readyState}` +
+            ` networkState=${videoElement.networkState}` +
+            ` paused=${videoElement.paused}` +
+            ` seeking=${videoElement.seeking}` +
+            ` rate=${videoElement.playbackRate}` +
+            ` buffered=${bufferedRanges.join(", ")}`
+        );
       }
     }, 1000);
   });
@@ -703,6 +731,11 @@
     if (debugLogInterval) {
       clearInterval(debugLogInterval);
     }
+    tapGestures.cancel();
+    if (doubleTapFeedbackTimeout) {
+      clearTimeout(doubleTapFeedbackTimeout);
+      doubleTapFeedbackTimeout = null;
+    }
 
     // Remove native backend event listeners (incl. background-audio lifecycle subs)
     for (const unlisten of nativeUnlisteners) {
@@ -1079,6 +1112,21 @@
   }
 
   function handlePause() {
+    // The element pausing is normally user intent, but a stall, a source change,
+    // or a competing controller can also do it — and the pause itself carries no
+    // reason. Log the element state so an unexplained pause/resume loop can be
+    // attributed from an adb capture instead of guessed at.
+    const el = videoElement;
+    console.log(
+      `[VideoPlayer] pause event — t=${el ? el.currentTime.toFixed(2) : "?"}` +
+        ` readyState=${el?.readyState}` +
+        ` networkState=${el?.networkState}` +
+        ` seeking=${el?.seeking}` +
+        ` ended=${el?.ended}` +
+        ` isSeeking=${isSeeking}` +
+        ` isBuffering=${isBuffering}` +
+        ` handoff=${handoffState.active}`
+    );
     isPlaying = false;
     stopTimeUpdates(); // Stop RAF loop when paused
     html5Adapter.reportState("paused", reportMediaId ?? null);
@@ -1122,11 +1170,33 @@
     const targetTime = parseFloat(input.value);
     // Update the displayed time immediately for smooth visual feedback
     currentTime = targetTime;
+    // The user has moved the value; the next release must commit it.
+    seekCommitArmed = true;
   }
 
-  async function handleSeekBarChange(e: Event) {
-    const input = e.target as HTMLInputElement;
-    const targetTime = parseFloat(input.value);
+  /**
+   * Seek-bar released — commit the value the user landed on, at most once.
+   *
+   * Wired to `touchend`/`mouseup` AND `change`, because `change` alone is not
+   * dependable: Android's WebView does not reliably fire it for a touch
+   * interaction on a range input, so the thumb moved to the tapped position but
+   * the seek never ran ("the bar moves, playback doesn't"). Engines that DO fire
+   * `change` deliver both signals, hence the arm/disarm — whichever arrives
+   * first commits and the other is a no-op.
+   */
+  function handleSeekBarRelease(e: Event) {
+    isDraggingSeekBar = false;
+    if (!seekCommitArmed) return;
+    seekCommitArmed = false;
+    const input = (e.currentTarget ?? e.target) as HTMLInputElement;
+    void commitSeek(parseFloat(input.value));
+  }
+
+  async function commitSeek(rawTarget: number) {
+    // Clamp strictly inside the media: the range input's max IS the duration, so
+    // dragging fully right would otherwise request a segment past the media end,
+    // which the server never produces (see END_SEEK_MARGIN_SECONDS).
+    const targetTime = clampSeekTarget(rawTarget, duration);
 
     // Set isSeeking immediately to prevent timeupdate from interfering
     isSeeking = true;
@@ -1192,9 +1262,13 @@
 
   function toggleBackgroundAudio() {
     backgroundAudioOn = !backgroundAudioOn;
+    console.log("[VideoPlayer] Background-audio toggle ->", backgroundAudioOn);
     // Arm/disarm native background-audio mode AND flip auto-PiP the other way,
     // so exactly one background behavior is active.
-    setBackgroundAudioEnabled(backgroundAudioOn);
+    const armed = setBackgroundAudioEnabled(backgroundAudioOn);
+    if (!armed) {
+      console.warn("[VideoPlayer] Background audio NOT armed natively (no bridge)");
+    }
     setAutoEnterEnabled(!backgroundAudioOn);
   }
 
@@ -1342,7 +1416,16 @@
   async function seekRelative(seconds: number) {
     isSeeking = true;
 
-    const newTime = Math.max(0, Math.min(duration, currentTime + seconds));
+    // The facade seeks by absolute position, so resolve the delta here —
+    // chaining off a still-in-flight target so rapid double taps accumulate
+    // instead of all resolving against the same not-yet-updated position.
+    const newTime = resolveSeekTarget({
+      delta: seconds,
+      reportedPosition: currentTime,
+      duration,
+      pendingTarget: pendingSeekTarget,
+    });
+    pendingSeekTarget = newTime;
 
     console.log("[VideoPlayer] Relative seek:", {
       offset: `${seconds > 0 ? "+" : ""}${seconds}s`,
@@ -1350,15 +1433,13 @@
       to: newTime.toFixed(2),
     });
 
-    // Call the unified handleSeekBarChange logic with the new time
-    // Create a synthetic event to reuse the existing logic
-    const syntheticEvent = {
-      target: {
-        value: newTime.toString()
-      }
-    } as unknown as Event;
-
-    await handleSeekBarChange(syntheticEvent);
+    // Same commit path as the seek bar — one place decides how a seek is issued.
+    try {
+      await commitSeek(newTime);
+    } finally {
+      // The player is authoritative again from here on.
+      if (pendingSeekTarget === newTime) pendingSeekTarget = null;
+    }
   }
 
   function handleKeydown(e: KeyboardEvent) {
@@ -1375,42 +1456,88 @@
       }
     } else if (e.key === "ArrowLeft") {
       e.preventDefault();
-      seekRelative(-10);
+      seekRelative(SEEK_BACKWARD_SECONDS);
     } else if (e.key === "ArrowRight") {
       e.preventDefault();
-      seekRelative(10);
+      seekRelative(SEEK_FORWARD_SECONDS);
     }
   }
 
+  /**
+   * Walk up from the touch target collecting the tag/attribute pairs
+   * `isControlSurfaceTouch` needs, so the rule itself stays DOM-free and testable.
+   */
+  function ancestorChain(target: EventTarget | null) {
+    const chain: Array<{
+      tag: string;
+      isPlayerControls?: boolean;
+      isPlayerSurface?: boolean;
+    }> = [];
+    let node = target as HTMLElement | null;
+    // Bounded walk: controls live a few levels below the player root, and
+    // stopping at <body> keeps this cheap and avoids depending on a bound ref.
+    while (node && node.tagName !== "BODY") {
+      chain.push({
+        tag: node.tagName ?? "",
+        isPlayerControls: node.dataset?.playerControls !== undefined,
+        isPlayerSurface: node.dataset?.playerSurface !== undefined,
+      });
+      node = node.parentElement;
+    }
+    return chain;
+  }
+
   // Touch gesture handlers
   function handleTouchStart(e: TouchEvent) {
+    // Taps on the controls belong to those controls. This listener is on the
+    // container and touch events bubble, so without this a tap on the bottom
+    // play button would toggle here AND again via the button's own click — the
+    // two cancelling out and leaving the control apparently dead (DR-098).
+    if (isControlSurfaceTouch(ancestorChain(e.target))) {
+      // The move handler must stay out of it too. It reads touchStartX/Y, which
+      // this early return leaves at the PREVIOUS gesture's values, so a seek-bar
+      // drag came out as a huge vertical delta: it was mis-read as a brightness
+      // swipe, which dimmed the screen and fired a spurious play/pause
+      // "correction" mid-drag (DR-098).
+      playerGestureActive = false;
+      return;
+    }
+    playerGestureActive = true;
+
     const touch = e.touches[0];
     touchStartX = touch.clientX;
     touchStartY = touch.clientY;
     touchStartTime = Date.now();
 
-    const now = Date.now();
-    const timeSinceLastTap = now - lastTapTime;
+    const outcome = registerTap(tapGestures, {
+      x: touch.clientX,
+      screenWidth: window.innerWidth,
+      now: Date.now(),
+    });
 
-    // Double tap detection (within 300ms)
-    if (timeSinceLastTap < 300 && timeSinceLastTap > 0) {
+    // Suppress the compatibility click this touch will synthesize.
+    lastTouchTapAt = Date.now();
+
+    if (outcome.action === "seek") {
       e.preventDefault();
-      handleDoubleTap(touch.clientX);
-      lastTapTime = 0; // Reset to prevent triple-tap
-      if (tapTimeout) {
-        clearTimeout(tapTimeout);
-        tapTimeout = null;
-      }
-    } else {
-      lastTapTime = now;
-      // Set timeout to clear if no second tap
-      tapTimeout = setTimeout(() => {
-        lastTapTime = 0;
-      }, 300);
+      handleDoubleTap(outcome.seekSeconds, outcome.feedback);
+      // Re-toggle so the first tap's toggle is undone: a double tap seeks and
+      // leaves the play state as it was (playing keeps playing, paused stays
+      // paused).
+      if (outcome.togglePlayPause) togglePlayPause();
+      return;
     }
+
+    // First tap: act now. Nothing is deferred, so there is no timer to race the
+    // compatibility click Android synthesizes after a touch tap (see DR-098).
+    togglePlayPause();
   }
 
   function handleTouchMove(e: TouchEvent) {
+    // Only a gesture that began on the bare video surface is ours. Re-checking
+    // the target here would not be enough: the touch that started on a control
+    // never recorded a start point, so any delta computed here is meaningless.
+    if (!playerGestureActive) return;
     if (!e.touches[0]) return;
 
     const touch = e.touches[0];
@@ -1420,6 +1547,15 @@
 
     // Minimum movement to register as swipe (50px)
     if (Math.abs(deltaY) > 50 && timeDelta > 50) {
+      // Only on the frame the gesture is first recognised as a swipe — this runs
+      // on every touchmove, and the correction below must happen exactly once.
+      if (!swipeGestureActive) {
+        // The touchstart already toggled play/pause (taps act immediately now),
+        // so undo it: a swipe must not change the play state. Forget the tap too,
+        // so it cannot pair with a later tap into a spurious seek.
+        togglePlayPause();
+        tapGestures.cancel();
+      }
       swipeGestureActive = true;
 
       // Brightness control on vertical swipe
@@ -1434,23 +1570,28 @@
   }
 
   function handleTouchEnd(e: TouchEvent) {
+    playerGestureActive = false;
     swipeGestureActive = false;
     swipeType = null;
   }
 
-  function handleDoubleTap(x: number) {
-    const screenWidth = window.innerWidth;
-    const isLeftSide = x < screenWidth / 2;
+  /**
+   * Mouse clicks toggle play/pause immediately. Touch taps are handled fully by
+   * `handleTouchStart`, so the compatibility click the browser synthesizes after
+   * a tap must be ignored or every tap toggles twice.
+   *
+   * Used by EVERY click target layered over the video, not just the <video>:
+   * pausing renders the full-screen play overlay, so the synthesized click lands
+   * on that button instead and would re-toggle straight back to playing.
+   */
+  function handleSurfaceClick(e: MouseEvent) {
+    if (isSynthesizedTouchClick(e.detail, Date.now(), lastTouchTapAt)) return;
+    togglePlayPause();
+  }
 
-    if (isLeftSide) {
-      // Double tap left: rewind 10 seconds
-      seekRelative(-10);
-      showDoubleTapFeedback = "left";
-    } else {
-      // Double tap right: forward 10 seconds
-      seekRelative(10);
-      showDoubleTapFeedback = "right";
-    }
+  function handleDoubleTap(seekSeconds: number, feedback: TapFeedback) {
+    seekRelative(seekSeconds);
+    showDoubleTapFeedback = feedback;
 
     // Hide feedback after animation
     if (doubleTapFeedbackTimeout) {
@@ -1612,7 +1753,7 @@
           onwaiting={handleWaiting}
           onplaying={handlePlaying}
           onloadstart={handleLoadStart}
-          onclick={togglePlayPause}
+          onclick={handleSurfaceClick}
         >
           <!-- Temporarily disabled to debug playback issues
           {#each subtitleTracks() as track}
@@ -1665,7 +1806,7 @@
         <div class="bg-white/20 rounded-full p-6 backdrop-blur-sm">
           <svg class="w-12 h-12 text-white" fill="currentColor" viewBox="0 0 24 24">
             <path d="M11.99 2C6.47 2 2 6.48 2 12s4.47 10 9.99 10C17.52 22 22 17.52 22 12S17.52 2 11.99 2zM12 20c-4.42 0-8-3.58-8-8s3.58-8 8-8 8 3.58 8 8-3.58 8-8 8zm1-13H11v6l5.25 3.15.75-1.23-4-2.42z" />
-            <text x="12" y="14" text-anchor="middle" font-size="6" fill="white" font-weight="bold">-10</text>
+            <text x="12" y="14" text-anchor="middle" font-size="6" fill="white" font-weight="bold">{SEEK_BACKWARD_SECONDS}</text>
           </svg>
         </div>
       </div>
@@ -1676,7 +1817,7 @@
         <div class="bg-white/20 rounded-full p-6 backdrop-blur-sm">
           <svg class="w-12 h-12 text-white" fill="currentColor" viewBox="0 0 24 24">
             <path d="M11.99 2C6.47 2 2 6.48 2 12s4.47 10 9.99 10C17.52 22 22 17.52 22 12S17.52 2 11.99 2zM12 20c-4.42 0-8-3.58-8-8s3.58-8 8-8 8 3.58 8 8-3.58 8-8 8zm1-13H11v6l5.25 3.15.75-1.23-4-2.42z" />
-            <text x="12" y="14" text-anchor="middle" font-size="6" fill="white" font-weight="bold">+10</text>
+            <text x="12" y="14" text-anchor="middle" font-size="6" fill="white" font-weight="bold">+{SEEK_FORWARD_SECONDS}</text>
           </svg>
         </div>
       </div>
@@ -1705,10 +1846,17 @@
         <div class="w-12 h-12 border-4 border-white border-t-transparent rounded-full animate-spin"></div>
       </div>
     {:else if !isPlaying}
-      <!-- Play/Pause overlay -->
+      <!-- Play overlay. Visually this IS the video surface, so it is marked
+           `data-player-surface`: it must keep participating in tap gestures even
+           though it is a <button>, or the second tap of a double tap (which lands
+           here, because the first tap paused and raised this overlay) is
+           discarded as "a tap on a control" and seeking dies. It still shares the
+           synthesized-click guard, since it appears exactly when a tap pauses.
+           See DR-098. -->
       <button
+        data-player-surface
         class="absolute inset-0 flex items-center justify-center bg-black/30"
-        onclick={togglePlayPause}
+        onclick={handleSurfaceClick}
         aria-label="Play"
       >
         <svg class="w-20 h-20 text-white" fill="currentColor" viewBox="0 0 24 24">
@@ -1756,8 +1904,10 @@
     {/if}
   </div>
 
-  <!-- Controls -->
+  <!-- Controls. `data-player-controls` marks this subtree as interactive so
+       container-level tap gestures ignore touches here (see DR-098). -->
   <div
+    data-player-controls
     class="absolute bottom-0 left-0 right-0 bg-gradient-to-t from-black/80 to-transparent p-4 transition-opacity duration-300"
     class:opacity-0={!showControls}
     class:pointer-events-none={!showControls}
@@ -1784,11 +1934,11 @@
           max={duration || 100}
           value={currentTime}
           oninput={handleSeekBarInput}
-          onchange={handleSeekBarChange}
+          onchange={handleSeekBarRelease}
           onmousedown={() => isDraggingSeekBar = true}
-          onmouseup={() => isDraggingSeekBar = false}
+          onmouseup={handleSeekBarRelease}
           ontouchstart={() => isDraggingSeekBar = true}
-          ontouchend={() => isDraggingSeekBar = false}
+          ontouchend={handleSeekBarRelease}
           class="flex-1 h-1 bg-white/30 rounded-full appearance-none cursor-pointer
                  [&::-webkit-slider-thumb]:appearance-none [&::-webkit-slider-thumb]:w-3 [&::-webkit-slider-thumb]:h-3
                  [&::-webkit-slider-thumb]:bg-white [&::-webkit-slider-thumb]:rounded-full"

src/lib/components/player/VideoPlayer.tapSurface.test.ts

@@ -0,0 +1,211 @@
+/**
+ * Behavioural regression tests for the video tap surface — rendered against the
+ * REAL component, not a hand-modelled DOM.
+ *
+ * TRACES: UR-005, UR-061 | DR-098 | UT-092
+ *
+ * Why this file exists:
+ *
+ * `tapGestures.test.ts` tests `registerTap` / `isControlSurfaceTouch` /
+ * `isSynthesizedTouchClick` as isolated pure functions. Every one of those tests
+ * passed while, on the device, in sequence: the player pause-looped, then
+ * pausing became impossible, then the bottom controls went dead, then
+ * double-tap-to-seek stopped working. The helpers were each behaving exactly as
+ * specified — the bugs were all in the *composition*: which element actually
+ * receives a tap once Svelte has re-rendered.
+ *
+ * Testing my own helpers could not catch that, and modelling the DOM by hand in
+ * a test just re-encodes the same wrong assumption. So these tests render
+ * VideoPlayer and dispatch real touch/click events at whatever element is
+ * genuinely on top, asserting user-visible outcomes ("a double tap seeks")
+ * rather than internals.
+ *
+ * The specific traps encoded here, each a bug that shipped:
+ *   - pausing renders a full-screen <button> play overlay OVER the video, so the
+ *     second tap of a double tap lands on a button, not the video;
+ *   - the browser synthesizes a `click` after a touch tap, which must not toggle
+ *     a second time, on ANY layered target;
+ *   - the bottom controls bar must drive its own buttons and NOT the container's
+ *     tap gestures.
+ */
+
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { render } from "@testing-library/svelte";
+import { tick } from "svelte";
+import VideoPlayer from "./VideoPlayer.svelte";
+import { SEEK_FORWARD_SECONDS } from "./tapGestures";
+
+// --- Mocks: everything VideoPlayer reaches for that is not the tap surface. ---
+
+const toggleSpy = vi.fn();
+const seekVideoSpy = vi.fn();
+const seekSpy = vi.fn();
+
+vi.mock("$app/navigation", () => ({ goto: vi.fn() }));
+
+vi.mock("$lib/player", () => ({
+  playerController: {
+    toggle: (...a: unknown[]) => {
+      toggleSpy(...a);
+      return Promise.resolve();
+    },
+    seekVideo: (...a: unknown[]) => {
+      seekVideoSpy(...a);
+      return Promise.resolve();
+    },
+    seek: (...a: unknown[]) => {
+      seekSpy(...a);
+      return Promise.resolve();
+    },
+    setActiveAdapter: vi.fn(),
+    clearActiveAdapter: vi.fn(),
+    getActiveAdapter: vi.fn(() => null),
+  },
+}));
+
+vi.mock("$lib/player/adapters/rustReportHost", () => ({
+  createRustReportHost: () => ({
+    onState: vi.fn(),
+    onPosition: vi.fn(),
+    onMediaLoaded: vi.fn(),
+    onEnded: vi.fn(),
+    onError: vi.fn(),
+    onStreamUrlChanged: vi.fn(),
+    onBuffering: vi.fn(),
+    onReady: vi.fn(),
+  }),
+}));
+
+vi.mock("$lib/player/html5Adapter", () => ({
+  reportState: vi.fn(),
+  reportPosition: vi.fn(),
+  reportMediaLoaded: vi.fn(),
+  resetReporting: vi.fn(),
+}));
+
+vi.mock("$lib/utils/pictureInPicture", () => ({
+  isPipSupported: () => false,
+  enterPip: vi.fn(),
+  setAutoEnterEnabled: vi.fn(),
+}));
+
+vi.mock("$lib/stores/auth", () => ({
+  auth: {
+    getRepository: () => ({ getHandle: () => "h", jrayActorsAt: async () => [] }),
+    subscribe: (fn: (v: unknown) => void) => {
+      fn({ isAuthenticated: true });
+      return () => {};
+    },
+  },
+}));
+
+const MEDIA = {
+  id: "item-1",
+  name: "Test Episode",
+  type: "Episode",
+  runTimeTicks: 6_000_000_000, // 600s
+} as any;
+
+/** Dispatch a touch at (x, y) on whatever element is topmost there. */
+function touchAt(el: Element, x: number) {
+  const touch = { clientX: x, clientY: 300 } as Touch;
+  el.dispatchEvent(
+    new TouchEvent("touchstart", {
+      bubbles: true,
+      cancelable: true,
+      touches: [touch] as unknown as Touch[],
+    })
+  );
+}
+
+function renderPlayer() {
+  return render(VideoPlayer, {
+    props: { media: MEDIA, streamUrl: "http://x/master.m3u8", onClose: vi.fn() },
+  });
+}
+
+describe("VideoPlayer tap surface (real component)", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it("a single tap on the video toggles play/pause exactly once", async () => {
+    const { container } = renderPlayer();
+    const video = container.querySelector("video");
+    expect(video).toBeTruthy();
+
+    touchAt(video!, 900);
+
+    expect(toggleSpy).toHaveBeenCalledTimes(1);
+  });
+
+  it("the synthesized click after a tap does not toggle a second time", async () => {
+    const { container } = renderPlayer();
+    const video = container.querySelector("video")!;
+
+    touchAt(video, 900);
+    // The compatibility click the browser fires after a touch tap. detail=0 is
+    // how engines mark it; a late real-detail click is covered by the recency
+    // guard, which this exercises too since it lands immediately.
+    video.dispatchEvent(new MouseEvent("click", { bubbles: true, detail: 0 }));
+
+    expect(toggleSpy).toHaveBeenCalledTimes(1);
+  });
+
+  it("a double tap seeks even though the first tap raised the play overlay", async () => {
+    // THE regression this file exists for. On device the first tap pauses, which
+    // makes Svelte render a full-screen <button> play overlay over the video —
+    // so the SECOND tap lands on a button, not the video. A control-surface
+    // guard that does not know about that overlay discards it and seeking dies.
+    //
+    // Reproducing it requires the overlay to actually render, which means
+    // driving `isPlaying` the way the real element does: via its `pause` event.
+    vi.useFakeTimers();
+    try {
+      const { container } = renderPlayer();
+      const video = container.querySelector("video")!;
+
+      // Tap 1 on the video.
+      touchAt(video, 900);
+
+      // The element reports it paused → isPlaying=false → overlay renders.
+      video.dispatchEvent(new Event("pause"));
+      await Promise.resolve();
+      await tick();
+
+      const overlay = container.querySelector("[data-player-surface]");
+      expect(overlay, "the play overlay should be covering the video").toBeTruthy();
+
+      vi.advanceTimersByTime(120); // inside DOUBLE_TAP_WINDOW_MS
+      // Tap 2 lands on the OVERLAY, exactly as on device.
+      touchAt(overlay!, 900);
+
+      // Either seek route is acceptable — which one runs depends on whether a
+      // video adapter is registered. What must hold is that a seek happened, to
+      // roughly the forward-skip target.
+      const calls = [...seekVideoSpy.mock.calls, ...seekSpy.mock.calls];
+      expect(calls.length).toBe(1);
+      const [position] = calls[0];
+      expect(position).toBeGreaterThan(0);
+      expect(position).toBeLessThanOrEqual(SEEK_FORWARD_SECONDS);
+    } finally {
+      vi.useRealTimers();
+    }
+  });
+
+  it("tapping the bottom play/pause button toggles once, not twice", async () => {
+    const { container } = renderPlayer();
+    const controls = container.querySelector("[data-player-controls]");
+    expect(controls).toBeTruthy();
+
+    const playBtn = controls!.querySelector("button");
+    expect(playBtn).toBeTruthy();
+
+    // A real press: touchstart bubbles to the container's gesture handler, then
+    // the button's own click fires. Only ONE toggle may result.
+    touchAt(playBtn!, 40);
+    playBtn!.dispatchEvent(new MouseEvent("click", { bubbles: true, detail: 1 }));
+
+    expect(toggleSpy).toHaveBeenCalledTimes(1);
+  });
+});

src/lib/components/player/VideoPlayer.touchScrub.test.ts

@@ -0,0 +1,218 @@
+/**
+ * VideoPlayer seek-bar TOUCH scrub regression tests (Android).
+ *
+ * Reported bug: on Android, dragging the progress bar does not change the
+ * playback location.
+ *
+ * The gesture listener lives on the outer container and touch events bubble.
+ * `handleTouchStart` ignores touches that land on a control (the seek bar is an
+ * <input>, inside `data-player-controls`) — but `handleTouchMove` does not, so a
+ * seek-bar drag is still interpreted as a container swipe. That mis-read swipe
+ * fires `togglePlayPause()` (undoing a first-tap toggle that never happened) and
+ * hijacks the drag into brightness control.
+ *
+ * The existing scrub regression tests only drive the slider with MOUSE events,
+ * which never reach the touch handlers — which is why this survived.
+ *
+ * The seek was also committed only from `change`, which Android's WebView does
+ * not reliably fire for a touch interaction on a range input — so a tap moved
+ * the thumb and no seek ever ran. Release now commits from touchend/mouseup too.
+ *
+ * TRACES: UR-005, UR-061 | DR-098, DR-099 | UT-089, UT-090
+ */
+
+import { describe, it, expect, vi, beforeEach } from "vitest";
+
+// ---- Mocks (must precede component import) --------------------------------
+
+const channelHandlers: Record<string, (event: any) => void> = {};
+vi.mock("@tauri-apps/api/event", () => ({
+  listen: vi.fn(async (channel: string, handler: any) => {
+    channelHandlers[channel] = handler;
+    return () => {
+      delete channelHandlers[channel];
+    };
+  }),
+}));
+
+vi.mock("@tauri-apps/api/core", () => ({
+  invoke: vi.fn(),
+}));
+
+const playerPlayItem = vi.fn(async () => ({
+  useHtml5Element: false,
+  backend: "exoplayer",
+  state: { kind: "playing" },
+}));
+const playerSeekVideo = vi.fn(async (_h: string, position: number) => ({
+  strategy: "native",
+  position,
+}));
+const playerStop = vi.fn(async () => ({}));
+const playerToggle = vi.fn(async () => ({ state: "playing" }));
+
+vi.mock("$lib/api/bindings", () => ({
+  commands: {
+    playerPlayItem: (...a: any[]) => playerPlayItem(...(a as [])),
+    playerSeekVideo: (...a: any[]) => playerSeekVideo(...(a as [string, number])),
+    playerStop: (...a: any[]) => playerStop(...(a as [])),
+    playerToggle: (...a: any[]) => playerToggle(...(a as [])),
+    playerPlay: vi.fn(async () => ({})),
+    playerPause: vi.fn(async () => ({})),
+    playerSetSleepTimer: vi.fn(async () => ({})),
+    playerCancelSleepTimer: vi.fn(async () => ({})),
+    playerSetSubtitleTrack: vi.fn(async () => ({})),
+    playerSwitchAudioTrack: vi.fn(async () => ({})),
+    storageGetSeriesAudioPreference: vi.fn(async () => null),
+    storageSaveSeriesAudioPreference: vi.fn(async () => ({})),
+  },
+  events: {
+    playerStatusEvent: { listen: vi.fn(async () => () => {}) },
+  },
+}));
+
+vi.mock("$lib/stores/auth", () => ({
+  auth: {
+    getUserId: () => "user-1",
+    getRepository: () => ({
+      getHandle: () => "repo-1",
+      getSubtitleUrl: async () => "",
+      jrayActorsAt: async () => [],
+    }),
+  },
+}));
+
+vi.mock("$app/navigation", () => ({
+  goto: vi.fn(),
+}));
+
+import { render, fireEvent, waitFor } from "@testing-library/svelte";
+import { tick } from "svelte";
+import VideoPlayer from "./VideoPlayer.svelte";
+import type { MediaItem } from "$lib/api/types";
+
+function makeEpisode(): MediaItem {
+  return {
+    id: "ep1",
+    name: "Episode 1",
+    kind: "episode",
+    durationMs: 24 * 60 * 1000, // 24 min
+  } as MediaItem;
+}
+
+async function mountAndroidPlayer() {
+  const utils = render(VideoPlayer, {
+    props: {
+      media: makeEpisode(),
+      streamUrl: "http://server/videos/ep1/master.m3u8",
+      mediaSourceId: "src-1",
+      needsTranscoding: false,
+      onClose: vi.fn(),
+    },
+  });
+
+  await waitFor(() => expect(playerPlayItem).toHaveBeenCalled());
+  await waitFor(() => expect(playerStop).toHaveBeenCalled());
+
+  const slider = utils.container.querySelector(
+    'input[type="range"]'
+  ) as HTMLInputElement;
+  const video = utils.container.querySelector("video") as HTMLVideoElement;
+  expect(slider).not.toBeNull();
+  return { ...utils, slider, video };
+}
+
+function touch(x: number, y: number) {
+  return { clientX: x, clientY: y } as Touch;
+}
+
+/**
+ * Drag the seek bar with TOUCH events, the way a finger does on Android.
+ *
+ * A real drag along the bar moves the finger far enough that the container's
+ * swipe detector (50px) would trigger if it were still listening.
+ */
+async function touchScrubTo(
+  slider: HTMLInputElement,
+  video: HTMLVideoElement,
+  target: number
+) {
+  await fireEvent.touchStart(slider, { touches: [touch(100, 700)] });
+  // Finger travels across the bar. Small vertical wander is normal for a thumb
+  // drag; the horizontal travel is what matters.
+  await fireEvent.touchMove(slider, { touches: [touch(400, 690)] });
+  slider.value = String(target);
+  await fireEvent.input(slider);
+  await fireEvent.touchMove(slider, { touches: [touch(700, 705)] });
+  await fireEvent.change(slider);
+  await fireEvent.touchEnd(slider, { touches: [] });
+  if (video) await fireEvent(video, new Event("seeked"));
+  await tick();
+}
+
+describe("VideoPlayer seek bar — touch drag (Android)", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    for (const key of Object.keys(channelHandlers)) delete channelHandlers[key];
+  });
+
+  it("a touch drag on the seek bar seeks to the dragged position", async () => {
+    const { slider, video } = await mountAndroidPlayer();
+
+    await touchScrubTo(slider, video, 600);
+
+    await waitFor(() =>
+      expect(playerSeekVideo).toHaveBeenCalledWith("repo-1", 600, "src-1", null, true)
+    );
+    expect(parseFloat(slider.value)).toBeCloseTo(600);
+  });
+
+  it("a touch drag on the seek bar never toggles play/pause", async () => {
+    const { slider, video } = await mountAndroidPlayer();
+
+    await touchScrubTo(slider, video, 600);
+
+    // The container gesture layer must stay out of a control drag entirely:
+    // no swipe mis-read, so no play/pause correction.
+    expect(playerToggle).not.toHaveBeenCalled();
+  });
+
+  it("commits the seek on touchend even when the engine never fires `change`", async () => {
+    const { slider, video } = await mountAndroidPlayer();
+
+    // Android's WebView does not reliably fire `change` for a touch interaction
+    // on a range input. A tap on the track still moves the thumb and fires
+    // `input` — the seek must be committed on release regardless.
+    await fireEvent.touchStart(slider, { touches: [touch(400, 700)] });
+    slider.value = "600";
+    await fireEvent.input(slider);
+    await fireEvent.touchEnd(slider, { touches: [] });
+    if (video) await fireEvent(video, new Event("seeked"));
+    await tick();
+
+    await waitFor(() =>
+      expect(playerSeekVideo).toHaveBeenCalledWith("repo-1", 600, "src-1", null, true)
+    );
+  });
+
+  it("commits the seek exactly once when both touchend and change fire", async () => {
+    const { slider, video } = await mountAndroidPlayer();
+
+    await touchScrubTo(slider, video, 600);
+
+    expect(playerSeekVideo).toHaveBeenCalledTimes(1);
+  });
+
+  it("a touch drag on the seek bar does not hijack into brightness control", async () => {
+    const { slider, video, container } = await mountAndroidPlayer();
+
+    await touchScrubTo(slider, video, 600);
+
+    // Brightness is applied as a CSS filter on the <video>; a control drag must
+    // leave it untouched.
+    const el = container.querySelector("video") as HTMLVideoElement | null;
+    if (el) {
+      expect(el.style.filter).toBe("brightness(1)");
+    }
+  });
+});

src/lib/components/player/tapGestures.test.ts

@@ -0,0 +1,276 @@
+import { describe, it, expect } from "vitest";
+import {
+  DOUBLE_TAP_WINDOW_MS,
+  SEEK_FORWARD_SECONDS,
+  SEEK_BACKWARD_SECONDS,
+  createTapGestureState,
+  registerTap,
+  resolveSeekTarget,
+  clampSeekTarget,
+  END_SEEK_MARGIN_SECONDS,
+  isSynthesizedTouchClick,
+  isControlSurfaceTouch,
+  TOUCH_CLICK_SUPPRESS_MS,
+} from "./tapGestures";
+
+const SCREEN_WIDTH = 1000;
+const LEFT = 100;
+const RIGHT = 900;
+
+function tap(state: ReturnType<typeof createTapGestureState>, x: number, at: number) {
+  return registerTap(state, { x, screenWidth: SCREEN_WIDTH, now: at });
+}
+
+/** Narrow a tap outcome to the seek variant, failing the test if it is not one. */
+function asSeek(outcome: ReturnType<typeof tap>) {
+  if (outcome.action !== "seek") {
+    throw new Error(`expected a seek outcome, got "${outcome.action}"`);
+  }
+  return outcome;
+}
+
+describe("tap gesture resolution", () => {
+  // Every tap acts IMMEDIATELY — there is no deferral and no timer.
+  //
+  //   1st tap: toggle play/pause
+  //   2nd tap: seek, then toggle play/pause AGAIN
+  //
+  // The second toggle undoes the first, so a double tap seeks while leaving the
+  // play state exactly as it was: playing -> jump and keep playing; paused ->
+  // jump and stay paused. The old design deferred the first tap behind a 300ms
+  // timer, which raced the synthesized click and produced a pause/unpause loop.
+
+  it("toggles play/pause immediately on the first tap", () => {
+    const state = createTapGestureState();
+    expect(tap(state, RIGHT, 1000)).toEqual({ action: "togglePlayPause" });
+  });
+
+  it("seeks forward 30s AND toggles again on a second right-side tap", () => {
+    const state = createTapGestureState();
+    tap(state, RIGHT, 1000);
+    const second = asSeek(tap(state, RIGHT, 1150));
+
+    expect(second.seekSeconds).toBe(SEEK_FORWARD_SECONDS);
+    expect(second.seekSeconds).toBe(30);
+    expect(second.feedback).toBe("right");
+    // The re-toggle is what preserves the play state across a double tap.
+    expect(second.togglePlayPause).toBe(true);
+  });
+
+  it("seeks back 10s AND toggles again on a second left-side tap", () => {
+    const state = createTapGestureState();
+    tap(state, LEFT, 1000);
+    const second = asSeek(tap(state, LEFT, 1100));
+
+    expect(second.seekSeconds).toBe(SEEK_BACKWARD_SECONDS);
+    expect(second.seekSeconds).toBe(-10);
+    expect(second.feedback).toBe("left");
+    expect(second.togglePlayPause).toBe(true);
+  });
+
+  it("net play state is unchanged by a double tap (two toggles cancel out)", () => {
+    const state = createTapGestureState();
+    let playing = true;
+    const apply = (outcome: ReturnType<typeof tap>) => {
+      if (outcome.action === "togglePlayPause") playing = !playing;
+      else if (outcome.action === "seek" && outcome.togglePlayPause) playing = !playing;
+    };
+
+    apply(tap(state, RIGHT, 1000)); // toggle -> paused
+    apply(tap(state, RIGHT, 1100)); // seek + toggle -> playing again
+    expect(playing).toBe(true);
+
+    // And from paused, a double tap leaves it paused.
+    playing = false;
+    apply(tap(state, RIGHT, 2000));
+    apply(tap(state, RIGHT, 2100));
+    expect(playing).toBe(false);
+  });
+
+  it("treats a tap after the window as a fresh first tap", () => {
+    const state = createTapGestureState();
+    tap(state, RIGHT, 1000);
+    const late = tap(state, RIGHT, 1000 + DOUBLE_TAP_WINDOW_MS + 1);
+
+    expect(late.action).toBe("togglePlayPause");
+  });
+
+  it("only ever has first and second taps — the tap after a pair is a fresh toggle", () => {
+    const state = createTapGestureState();
+    tap(state, RIGHT, 1000);
+    expect(tap(state, RIGHT, 1100).action).toBe("seek");
+
+    // The pair is consumed. The next tap is a FIRST tap again, so it toggles
+    // play/pause — there is no "third tap" concept.
+    expect(tap(state, RIGHT, 1200).action).toBe("togglePlayPause");
+  });
+
+  it("accumulates repeated double taps on the same side", () => {
+    const state = createTapGestureState();
+    tap(state, RIGHT, 1000);
+    const a = asSeek(tap(state, RIGHT, 1100));
+    tap(state, RIGHT, 1200);
+    const b = asSeek(tap(state, RIGHT, 1300));
+
+    expect(a.seekSeconds).toBe(30);
+    expect(b.seekSeconds).toBe(30);
+  });
+
+  it("uses the tap side, so a double tap split across halves follows the second tap", () => {
+    const state = createTapGestureState();
+    tap(state, LEFT, 1000);
+    const second = asSeek(tap(state, RIGHT, 1100));
+
+    expect(second.seekSeconds).toBe(SEEK_FORWARD_SECONDS);
+    expect(second.feedback).toBe("right");
+  });
+
+  it("cancel() makes the next tap a fresh first tap (swipe interrupted the pair)", () => {
+    const state = createTapGestureState();
+    tap(state, RIGHT, 1000);
+    state.cancel();
+
+    // Without cancel() this would have been the seeking second tap.
+    expect(tap(state, RIGHT, 1100).action).toBe("togglePlayPause");
+  });
+});
+
+describe("seek target resolution", () => {
+  const DURATION = 600;
+
+  it("adds the delta to the reported position", () => {
+    expect(resolveSeekTarget({ delta: 30, reportedPosition: 100, duration: DURATION })).toBe(130);
+  });
+
+  it("clamps to zero when rewinding past the start", () => {
+    expect(resolveSeekTarget({ delta: -10, reportedPosition: 4, duration: DURATION })).toBe(0);
+  });
+
+  it("clamps short of the duration when skipping past the end", () => {
+    // Never land exactly on `duration`: hls.js would then request the segment
+    // that starts at/after the media end, which the server never produces —
+    // the fetch times out and the gap-controller stalls in a pause loop.
+    expect(resolveSeekTarget({ delta: 30, reportedPosition: 590, duration: DURATION })).toBe(
+      DURATION - END_SEEK_MARGIN_SECONDS
+    );
+  });
+
+  it("keeps the end clamp strictly inside the media for a long transcoded item", () => {
+    // Regression: seeking near the end of a ~105min transcoded item clamped to
+    // the exact runtime (6330.324s), making hls.js fetch segment 1055 which
+    // starts at 6336.33s — past the end. That segment 404s/times out forever.
+    const runtime = 6330.324;
+    const target = resolveSeekTarget({ delta: 30, reportedPosition: 6320, duration: runtime });
+
+    expect(target).toBeLessThan(runtime);
+    expect(target).toBeCloseTo(runtime - END_SEEK_MARGIN_SECONDS, 5);
+  });
+
+  it("does not clamp below zero for media shorter than the end margin", () => {
+    expect(resolveSeekTarget({ delta: 30, reportedPosition: 1, duration: 1 })).toBe(0);
+  });
+
+  it("chains off a pending target so rapid taps do not compound off a stale position", () => {
+    // The player has not yet reported the first seek's result, so the
+    // reported position is still the pre-seek value.
+    const first = resolveSeekTarget({ delta: 30, reportedPosition: 100, duration: DURATION });
+    const second = resolveSeekTarget({
+      delta: 30,
+      reportedPosition: 100,
+      duration: DURATION,
+      pendingTarget: first,
+    });
+
+    expect(second).toBe(160);
+  });
+
+  it("ignores a pending target once the player has caught up past it", () => {
+    const target = resolveSeekTarget({
+      delta: 30,
+      reportedPosition: 200,
+      duration: DURATION,
+      pendingTarget: 130,
+    });
+
+    expect(target).toBe(230);
+  });
+
+  it("falls back to the delta alone when duration is unknown", () => {
+    expect(resolveSeekTarget({ delta: 30, reportedPosition: 100, duration: 0 })).toBe(130);
+  });
+});
+
+describe("control-surface touches are not gestures", () => {
+  // Regression: the gesture listener is on the outer container and touch events
+  // bubble, so tapping the bottom play/pause button ran the gesture handler
+  // (toggle #1) AND the button's own click handler (toggle #2). The two
+  // cancelled out and the control appeared dead.
+  it("treats a tap on a button as a control, not a gesture", () => {
+    expect(isControlSurfaceTouch([{ tag: "svg" }, { tag: "button" }, { tag: "div" }])).toBe(true);
+  });
+
+  it("treats the seek bar input as a control", () => {
+    expect(isControlSurfaceTouch([{ tag: "input" }, { tag: "div" }])).toBe(true);
+  });
+
+  it("treats anything inside the controls bar as a control", () => {
+    expect(
+      isControlSurfaceTouch([{ tag: "span" }, { tag: "div", isPlayerControls: true }])
+    ).toBe(true);
+  });
+
+  it("lets a tap on the bare video surface through as a gesture", () => {
+    expect(isControlSurfaceTouch([{ tag: "video" }, { tag: "div" }, { tag: "div" }])).toBe(false);
+  });
+
+  it("is case-insensitive about tag names", () => {
+    expect(isControlSurfaceTouch([{ tag: "BUTTON" }])).toBe(true);
+  });
+});
+
+describe("synthesized touch-click suppression", () => {
+  // Regression: pausing renders a full-screen play-overlay button over the
+  // video, so the compatibility click Android synthesizes from the tap lands on
+  // the OVERLAY, not the <video>. With no guard there it re-toggled and undid
+  // the pause — pausing looked impossible while unpausing worked fine (the
+  // overlay is removed when playing, so nothing intercepted that direction).
+  it("suppresses a click with detail 0 (clearly synthesized)", () => {
+    expect(isSynthesizedTouchClick(0, 10_000, 0)).toBe(true);
+  });
+
+  it("suppresses a real-detail click that closely follows a touch tap", () => {
+    const tapAt = 10_000;
+    expect(isSynthesizedTouchClick(1, tapAt + 120, tapAt)).toBe(true);
+    expect(isSynthesizedTouchClick(1, tapAt + TOUCH_CLICK_SUPPRESS_MS - 1, tapAt)).toBe(true);
+  });
+
+  it("allows a genuine mouse click well after any touch", () => {
+    const tapAt = 10_000;
+    expect(isSynthesizedTouchClick(1, tapAt + TOUCH_CLICK_SUPPRESS_MS + 1, tapAt)).toBe(false);
+  });
+
+  it("allows a genuine mouse click when no touch has ever happened", () => {
+    expect(isSynthesizedTouchClick(1, 10_000, 0)).toBe(false);
+  });
+});
+
+describe("seek target clamping (shared by skip and seek-bar drag)", () => {
+  it("keeps a mid-stream target untouched", () => {
+    expect(clampSeekTarget(100, 600)).toBe(100);
+  });
+
+  it("pulls a drag to the very end back inside the media", () => {
+    // The seek bar's max IS the duration, so dragging fully right yields
+    // exactly `duration` — the value that triggers the dead-segment stall.
+    expect(clampSeekTarget(6330.324, 6330.324)).toBeCloseTo(6330.324 - END_SEEK_MARGIN_SECONDS, 5);
+  });
+
+  it("clamps negative and non-finite targets to zero", () => {
+    expect(clampSeekTarget(-5, 600)).toBe(0);
+    expect(clampSeekTarget(NaN, 600)).toBe(0);
+  });
+
+  it("leaves the target alone when the duration is unknown", () => {
+    expect(clampSeekTarget(500, 0)).toBe(500);
+  });
+});

src/lib/components/player/tapGestures.ts

@@ -0,0 +1,234 @@
+/**
+ * Tap-gesture interpretation for the video player surface.
+ *
+ * Every tap acts IMMEDIATELY — there are only first and second taps, and no
+ * deferral:
+ *
+ *   1st tap: toggle play/pause
+ *   2nd tap (within the window): seek, then toggle play/pause AGAIN
+ *
+ * The second toggle undoes the first, so a double tap seeks while leaving the
+ * play state exactly as it started — playing stays playing, paused stays paused.
+ *
+ * This replaced a design that deferred the first tap behind a 300ms timer so it
+ * could be cancelled if a second tap arrived. That deferral raced the
+ * compatibility `click` Android's WebView synthesizes after a touch tap: the
+ * timer cleared its own handle *before* running the toggle, reopening the guard
+ * that was meant to suppress the late click, which then toggled a second time.
+ * The result was a play/pause loop about a second apart. Acting immediately
+ * removes the timer, the window race, and the loop.
+ *
+ * TRACES: UR-005, UR-061 | DR-092, DR-095, DR-098 | UT-085, UT-086, UT-087, UT-088
+ */
+
+/** A second tap within this window pairs with the previous one (seek + re-toggle). */
+export const DOUBLE_TAP_WINDOW_MS = 300;
+
+/**
+ * How long after a touch tap a mouse `click` is assumed to be the compatibility
+ * event the browser synthesizes from that touch. Android's WebView can deliver it
+ * noticeably late, so this is generous.
+ */
+export const TOUCH_CLICK_SUPPRESS_MS = 700;
+
+/**
+ * Whether a touch landed on an interactive control rather than the bare video
+ * surface, and so must NOT be interpreted as a play/pause or seek gesture.
+ *
+ * The gesture listener sits on the outer container, and touch events bubble, so
+ * without this a tap on the bottom control bar runs the gesture handler (toggle
+ * #1) *and* the button's own click handler (toggle #2) — the two cancel out and
+ * the button appears dead. Buttons, links, inputs (the seek bar), and anything
+ * inside an element marked `data-player-controls` are treated as controls.
+ *
+ * Takes the ancestor chain as plain tag/attribute pairs so the rule is unit
+ * testable without a DOM.
+ */
+export function isControlSurfaceTouch(
+  ancestors: Array<{ tag: string; isPlayerControls?: boolean; isPlayerSurface?: boolean }>
+): boolean {
+  const INTERACTIVE = new Set(["button", "a", "input", "select", "textarea", "label"]);
+  for (const node of ancestors) {
+    // `data-player-surface` wins over the tag check: the full-screen play overlay
+    // is a <button> but is visually the video itself, and must keep taking tap
+    // gestures — otherwise the second tap of a double tap (which lands on it,
+    // because the first tap paused and raised it) is discarded and seeking dies.
+    if (node.isPlayerSurface === true) return false;
+    if (node.isPlayerControls === true) return true;
+    if (INTERACTIVE.has(node.tag.toLowerCase())) return true;
+  }
+  return false;
+}
+
+/**
+ * Whether a `click` should be ignored because a touch tap already handled it.
+ *
+ * EVERY click target layered over the video must consult this — not just the
+ * `<video>` element. Pausing swaps in a full-screen play-overlay button, so the
+ * synthesized click lands on *that* button rather than the video, and an
+ * unguarded handler there re-toggles and undoes the pause (pause appeared
+ * impossible while unpause worked, because unpausing removes the overlay).
+ *
+ * `detail === 0` catches the synthesized click on engines that report it; the
+ * recency check covers engines that report a real `detail`.
+ */
+export function isSynthesizedTouchClick(
+  detail: number,
+  now: number,
+  lastTouchTapAt: number
+): boolean {
+  if (detail === 0) return true;
+  return now - lastTouchTapAt < TOUCH_CLICK_SUPPRESS_MS;
+}
+
+/** Double tap on the right half: skip forward. */
+export const SEEK_FORWARD_SECONDS = 30;
+
+/** Double tap on the left half: skip back. */
+export const SEEK_BACKWARD_SECONDS = -10;
+
+export type TapFeedback = "left" | "right";
+
+export type TapOutcome =
+  /** First tap: toggle play/pause right now. */
+  | { action: "togglePlayPause" }
+  /**
+   * Second tap: seek, and toggle play/pause again so the first tap's toggle is
+   * undone and the play state survives the double tap unchanged.
+   */
+  | {
+      action: "seek";
+      seekSeconds: number;
+      feedback: TapFeedback;
+      togglePlayPause: true;
+    };
+
+export interface TapInput {
+  /** Tap x position, viewport pixels. */
+  x: number;
+  screenWidth: number;
+  now: number;
+}
+
+export interface TapGestureState {
+  /**
+   * Forget the previous tap, so the next one is treated as a first tap. Used
+   * when the gesture turns out to be a swipe.
+   */
+  cancel(): void;
+}
+
+interface InternalState extends TapGestureState {
+  lastTapTime: number;
+}
+
+export function createTapGestureState(): TapGestureState {
+  const state: InternalState = {
+    lastTapTime: 0,
+    cancel() {
+      state.lastTapTime = 0;
+    },
+  };
+  return state;
+}
+
+/**
+ * Classify a tap and return the action to perform *now*.
+ *
+ * A tap that closely follows another is the second of a pair: it seeks and
+ * re-toggles play/pause (undoing the first tap's toggle). Any other tap is a
+ * first tap and simply toggles. Nothing is deferred, so there is no window to
+ * race and no third-tap case — a consumed pair resets the state.
+ */
+export function registerTap(state: TapGestureState, input: TapInput): TapOutcome {
+  const s = state as InternalState;
+  const sinceLastTap = input.now - s.lastTapTime;
+
+  if (s.lastTapTime > 0 && sinceLastTap > 0 && sinceLastTap < DOUBLE_TAP_WINDOW_MS) {
+    s.lastTapTime = 0; // pair consumed; the next tap is a first tap again
+    const isLeftSide = input.x < input.screenWidth / 2;
+    return isLeftSide
+      ? {
+          action: "seek",
+          seekSeconds: SEEK_BACKWARD_SECONDS,
+          feedback: "left",
+          togglePlayPause: true,
+        }
+      : {
+          action: "seek",
+          seekSeconds: SEEK_FORWARD_SECONDS,
+          feedback: "right",
+          togglePlayPause: true,
+        };
+  }
+
+  s.lastTapTime = input.now;
+  return { action: "togglePlayPause" };
+}
+
+/**
+ * Safety margin (seconds) kept between a clamped seek target and the media end.
+ *
+ * Landing *exactly* on `duration` makes hls.js request the segment whose start
+ * time is at/after the end of the media. The server never produces that segment,
+ * so the fetch times out and hls.js' gap-controller stalls forever at the last
+ * buffered position — surfacing as "unpausing bounces straight back to paused".
+ * One segment length (~6s for Jellyfin's ts segments) is comfortably clear of
+ * the final segment boundary.
+ */
+export const END_SEEK_MARGIN_SECONDS = 6;
+
+/**
+ * Clamp an absolute seek target into the safely-playable range.
+ *
+ * Shared by the relative-skip path ({@link resolveSeekTarget}) and the seek-bar
+ * drag path, which can otherwise land exactly on `duration` because the range
+ * input's `max` is the duration itself.
+ */
+export function clampSeekTarget(target: number, duration: number): number {
+  if (!Number.isFinite(target) || target < 0) return 0;
+  if (duration > 0 && target > duration - END_SEEK_MARGIN_SECONDS) {
+    return Math.max(0, duration - END_SEEK_MARGIN_SECONDS);
+  }
+  return target;
+}
+
+export interface SeekTargetInput {
+  /** Relative offset in seconds (negative rewinds). */
+  delta: number;
+  /** Latest position reported by the player — the authoritative source. */
+  reportedPosition: number;
+  /** Media duration; 0/unknown disables the upper clamp. */
+  duration: number;
+  /**
+   * Target of a seek already requested but not yet reflected in
+   * `reportedPosition`. Consecutive double taps chain off this so they add up
+   * instead of all resolving against the same stale position.
+   */
+  pendingTarget?: number | null;
+}
+
+/**
+ * Resolve a relative skip to the absolute position the facade expects.
+ *
+ * The player facade seeks by absolute position only (the backend picks the seek
+ * strategy), so the delta is applied here — against the pending target when one
+ * is still in flight and still ahead of what the player has reported.
+ */
+export function resolveSeekTarget(input: SeekTargetInput): number {
+  const { delta, reportedPosition, duration, pendingTarget } = input;
+
+  const base =
+    pendingTarget != null && Math.abs(pendingTarget - reportedPosition) > 0.5 && pendingTarget > reportedPosition
+      ? pendingTarget
+      : reportedPosition;
+
+  const target = base + delta;
+  if (target < 0) return 0;
+  // Clamp strictly inside the media — see END_SEEK_MARGIN_SECONDS. Guard against
+  // going negative on media shorter than the margin itself.
+  if (duration > 0 && target > duration) {
+    return Math.max(0, duration - END_SEEK_MARGIN_SECONDS);
+  }
+  return target;
+}

src/lib/player/adapters/html5Adapter.test.ts

@@ -95,6 +95,63 @@ describe("Html5PlayerAdapter", () => {
     expect(video.play).toHaveBeenCalledTimes(1);
   });
 
+  // A stalling HLS stream makes hls.js' gap-controller nudge the element, which
+  // aborts an in-flight play(). That AbortError is transient — the element is
+  // still trying to play — so it must not be surfaced as a player error, or the
+  // UI reports failure ~once a second for the whole stall.
+  it("play() does not report an interrupted-by-pause AbortError as an error", async () => {
+    const abort = new DOMException(
+      "The play() request was interrupted by a call to pause().",
+      "AbortError"
+    );
+    video.play = vi.fn(async () => {
+      throw abort;
+    });
+
+    await adapter.play();
+
+    expect(host.onError).not.toHaveBeenCalled();
+  });
+
+  it("play() still reports a genuine failure", async () => {
+    video.play = vi.fn(async () => {
+      throw new DOMException("no supported source", "NotSupportedError");
+    });
+
+    await adapter.play();
+
+    expect(host.onError).toHaveBeenCalledTimes(1);
+    expect(String((host.onError as any).mock.calls[0][0])).toContain("play() failed");
+  });
+
+  it("play() coalesces concurrent attempts into one element.play() call", async () => {
+    // During a stall the UI and recovery paths can both ask to play. Stacking
+    // element.play() calls is what generates the AbortError storm.
+    let resolvePlay: () => void = () => {};
+    video.play = vi.fn(
+      () =>
+        new Promise<void>((r) => {
+          resolvePlay = () => {
+            video.paused = false;
+            r();
+          };
+        })
+    );
+
+    const first = adapter.play();
+    const second = adapter.play();
+    resolvePlay();
+    await Promise.all([first, second]);
+
+    expect(video.play).toHaveBeenCalledTimes(1);
+  });
+
+  it("play() works again after a previous attempt settled", async () => {
+    await adapter.play();
+    await adapter.play();
+    expect(video.play).toHaveBeenCalledTimes(2);
+  });
+
   it("pause() calls element.pause()", async () => {
     video.paused = false;
     await adapter.pause();

src/lib/player/adapters/html5Adapter.ts

@@ -16,7 +16,7 @@
  * intents flowing through the PlayerAdapter interface while preserving the
  * hard-won element behavior verbatim.
  *
- * TRACES: UR-003, UR-005, UR-020, UR-021 | DR-001, DR-023, DR-024, DR-028
+ * TRACES: UR-003, UR-005, UR-020, UR-021 | DR-001, DR-023, DR-024, DR-028, DR-096
  */
 
 import type { AdapterHost, PlayerAdapter, PlayerLoadOptions } from "./types";
@@ -41,10 +41,24 @@ export interface Html5ElementBridge {
   getMediaSourceId(): string | null;
 }
 
+/**
+ * True for the `AbortError` the browser raises when a pending `play()` promise is
+ * cancelled by a `pause()` (or a source/seek change). It signals "that specific
+ * play attempt was superseded", not "playback failed" — hls.js' stall recovery
+ * produces it routinely, so it must not reach the player's error channel.
+ */
+function isPlayInterruptedError(err: unknown): boolean {
+  if (!err || typeof err !== "object") return false;
+  const { name, message } = err as { name?: string; message?: string };
+  return name === "AbortError" || (message ?? "").includes("interrupted");
+}
+
 export class Html5PlayerAdapter implements PlayerAdapter {
   readonly kind = "html5" as const;
 
   private attachedElement: HTMLVideoElement | null = null;
+  /** In-flight play() attempt, so concurrent callers share one element.play(). */
+  private pendingPlay: Promise<void> | null = null;
   private host: AdapterHost;
   private bridge: Html5ElementBridge;
 
@@ -81,12 +95,31 @@ export class Html5PlayerAdapter implements PlayerAdapter {
   async play(): Promise<void> {
     const el = this.element;
     if (!el) return;
-    try {
-      await el.play();
-      // handlePlay on the element reports "playing"; no double-report here.
-    } catch (err) {
-      this.host.onError(`play() failed: ${err}`);
-    }
+    // Coalesce concurrent attempts. While an HLS stream stalls, the UI and the
+    // gap-controller recovery path can both ask to play; stacking element.play()
+    // calls is what turns one stall into an AbortError storm.
+    if (this.pendingPlay) return this.pendingPlay;
+
+    this.pendingPlay = (async () => {
+      try {
+        await el.play();
+        // handlePlay on the element reports "playing"; no double-report here.
+      } catch (err) {
+        // A play() aborted by a pause() is transient, not a failure: hls.js
+        // nudges the element to recover from a stall, which cancels the pending
+        // play promise while the element keeps trying. Surfacing it would report
+        // an error roughly once a second for the duration of the stall.
+        if (isPlayInterruptedError(err)) {
+          console.debug("[Html5PlayerAdapter] play() interrupted by pause (stall recovery)");
+        } else {
+          this.host.onError(`play() failed: ${err}`);
+        }
+      } finally {
+        this.pendingPlay = null;
+      }
+    })();
+
+    return this.pendingPlay;
   }
 
   async pause(): Promise<void> {

src/lib/player/adapters/nativeAdapter.ts

@@ -7,11 +7,19 @@
  * hls.js. State reporting is unnecessary here because the native backend emits
  * events directly — the adapter's job is only to forward control intents.
  *
- * NOTE: On current Tauri, native Android video rendering is blocked upstream
- * (transparent webview / SurfaceView compositing — tauri#10152), so video on
- * Android currently runs through the HTML5 adapter via the interim override in
- * the factory. This adapter exists for the audio/native path and for when that
- * upstream limitation is resolved.
+ * NOTE: This adapter is currently unreachable — `createAdapter()` hardcodes the
+ * HTML5 kind, so Android video runs through Html5PlayerAdapter.
+ *
+ * That override was introduced citing tauri#10152 as an upstream blocker. That
+ * is no longer accurate: #10152 is a stale *feature request* (dead since
+ * 2024-07-01) asking that `transparent` not be desktop-only, and the capability
+ * shipped in tauri commit 27d01834 (2024-09-02). The related black/white-screen
+ * bug (tauri#8381, #9408) was a broken JNI signature for setBackgroundColor,
+ * fixed in wry 0.39.4; we ship wry 0.55.x.
+ *
+ * What is genuinely unproven is SurfaceView-behind-WebView *compositing* on
+ * Tauri Android — nothing upstream blocks it, and nothing upstream demonstrates
+ * it either. docs/specs/android-native-video-spike.md tracks that experiment.
  *
  * TRACES: UR-003, UR-005 | DR-004, DR-028
  */

src/lib/player/index.ts

@@ -12,7 +12,7 @@
  * derived + merged (remote-session-aware) stores so UI can import state and
  * actions from one place, in both local and remote modes.
  *
- * TRACES: UR-005 | DR-001, DR-009
+ * TRACES: UR-005 | DR-001, DR-009, DR-097 | UT-091
  */
 
 import { get } from "svelte/store";
@@ -83,18 +83,29 @@ function requireHandle(): string {
 // Transport controls (no repository handle required)
 // ---------------------------------------------------------------------------
 
+// Transport intents ALWAYS go to the backend, in both native and HTML5 modes.
+//
+// These used to short-circuit into the active video adapter, which made the
+// webview the decider: `adapter.toggle()` read `el.paused` off the DOM and
+// flipped the element, so Rust never saw the intent. `el.paused` flips
+// transiently while an element buffers or settles a seek, so two intents
+// ~150ms apart could read different values and take opposing actions — a
+// self-sustaining play/pause loop.
+//
+// Now Rust decides from PlayerController state and drives the element back
+// through a `ControlCommand` event (handled in playerEvents.ts), the same
+// "backend decides, adapter executes the primitive" split used by
+// player_seek_video. Do NOT reintroduce an adapter short-circuit here.
+
 async function play() {
-  if (activeAdapter) return void (await activeAdapter.play());
   await commands.playerPlay();
 }
 
 async function pause() {
-  if (activeAdapter) return void (await activeAdapter.pause());
   await commands.playerPause();
 }
 
 async function toggle() {
-  if (activeAdapter) return void (await activeAdapter.toggle());
   await commands.playerToggle();
 }
 

src/lib/player/transport.authority.test.ts

@@ -0,0 +1,113 @@
+/**
+ * Transport authority: play/pause/toggle are DECIDED in Rust, never in the webview.
+ *
+ * TRACES: UR-005 | DR-097 | UT-091
+ *
+ * The frontend used to short-circuit transport controls whenever a video adapter
+ * was registered: `toggle()` read `el.paused` off the DOM and flipped the element
+ * directly, so the Rust `PlayerController` never saw the intent and could not
+ * serialise competing ones. Because `el.paused` flips transiently while an HTML5
+ * element buffers or settles a seek, two intents arriving ~150ms apart could read
+ * *different* values and perform *opposing* actions — one playing, one pausing —
+ * which is the self-sustaining play/pause loop observed on Android.
+ *
+ * The rule these tests pin: a transport intent always reaches the backend. Rust
+ * decides play-vs-pause from controller state and drives the webview element back
+ * through a ControlCommand event (the same "backend decides, adapter executes"
+ * split `player_seek_video` already uses).
+ */
+
+import { describe, it, expect, vi, beforeEach } from "vitest";
+
+const mockCommands = {
+  playerPlay: vi.fn(async () => ({})),
+  playerPause: vi.fn(async () => ({})),
+  playerToggle: vi.fn(async () => ({})),
+  playerStop: vi.fn(async () => ({})),
+};
+
+vi.mock("$lib/api/bindings", () => ({
+  commands: mockCommands,
+  // Stores pulled in transitively subscribe to typed events at module load.
+  events: {
+    playerStatusEvent: { listen: vi.fn(async () => () => {}) },
+    downloadEvent: { listen: vi.fn(async () => () => {}) },
+    searchEvent: { listen: vi.fn(async () => () => {}) },
+  },
+}));
+
+vi.mock("$lib/stores/auth", () => ({
+  auth: {
+    subscribe: (fn: (v: unknown) => void) => {
+      fn({ isAuthenticated: true });
+      return () => {};
+    },
+    getRepository: () => ({ getHandle: () => "handle-1" }),
+  },
+}));
+
+/** A video adapter that records whether the facade reached into it directly. */
+function makeAdapter() {
+  return {
+    kind: "html5" as const,
+    play: vi.fn(async () => {}),
+    pause: vi.fn(async () => {}),
+    toggle: vi.fn(async () => true),
+    seekElement: vi.fn(async () => {}),
+    reloadSource: vi.fn(async () => {}),
+    attach: vi.fn(),
+    dispose: vi.fn(async () => {}),
+    setVolume: vi.fn(),
+    setMuted: vi.fn(),
+    selectSubtitle: vi.fn(async () => {}),
+    getPosition: vi.fn(() => 0),
+    load: vi.fn(async () => {}),
+  };
+}
+
+describe("transport authority lives in Rust", () => {
+  let playerController: any;
+  let adapter: ReturnType<typeof makeAdapter>;
+
+  beforeEach(async () => {
+    vi.clearAllMocks();
+    vi.resetModules();
+    ({ playerController } = await import("./index"));
+    adapter = makeAdapter();
+    playerController.setActiveAdapter(adapter);
+  });
+
+  it("routes toggle to the backend even when a video adapter is active", async () => {
+    await playerController.toggle();
+
+    expect(mockCommands.playerToggle).toHaveBeenCalledTimes(1);
+    // The webview must NOT decide play-vs-pause from the DOM.
+    expect(adapter.toggle).not.toHaveBeenCalled();
+  });
+
+  it("routes play to the backend even when a video adapter is active", async () => {
+    await playerController.play();
+
+    expect(mockCommands.playerPlay).toHaveBeenCalledTimes(1);
+    expect(adapter.play).not.toHaveBeenCalled();
+  });
+
+  it("routes pause to the backend even when a video adapter is active", async () => {
+    await playerController.pause();
+
+    expect(mockCommands.playerPause).toHaveBeenCalledTimes(1);
+    expect(adapter.pause).not.toHaveBeenCalled();
+  });
+
+  it("still routes transport to the backend with no adapter (audio path unchanged)", async () => {
+    playerController.clearActiveAdapter();
+
+    await playerController.toggle();
+    await playerController.play();
+    await playerController.pause();
+
+    expect(mockCommands.playerToggle).toHaveBeenCalledTimes(1);
+    expect(mockCommands.playerPlay).toHaveBeenCalledTimes(1);
+    expect(mockCommands.playerPause).toHaveBeenCalledTimes(1);
+  });
+});

src/lib/services/playerEvents.ts

@@ -5,7 +5,7 @@
  * frontend stores accordingly. This enables push-based updates instead
  * of polling.
  *
- * TRACES: UR-005, UR-019, UR-023, UR-026 | DR-001, DR-028, DR-047
+ * TRACES: UR-005, UR-019, UR-023, UR-026 | DR-001, DR-028, DR-047, DR-097
  */
 
 import { type UnlistenFn } from "@tauri-apps/api/event";
@@ -306,9 +306,15 @@ function handleSleepTimerChanged(mode: SleepTimerMode, remainingSeconds: number)
 
 /**
  * Route a backend-originated control command to the active player adapter, so a
- * backend intent (lockscreen/remote/sleep) can drive the webview <video> element
- * that Rust cannot reach directly. No-op when no video adapter is active (audio
- * playback is already fully backend-driven).
+ * backend intent can drive the webview <video>/<audio> element that Rust cannot
+ * reach directly. No-op when no adapter is active (native playback is already
+ * fully backend-driven).
+ *
+ * This is the EXECUTION half of transport authority: for webview-rendered media
+ * the Rust controller decides play-vs-pause from the state the element reported
+ * and emits it here as a ControlCommand. UI intents go *to* the backend (see the
+ * facade in $lib/player) and come back through this path — never short-circuited
+ * in the webview, which is what caused the DR-097 pause loop.
  */
 function handleControlCommand(action: string, position: number | null): void {
   const adapter = playerController.getActiveAdapter();

src/lib/stores/library.ts

@@ -5,7 +5,7 @@ import { writable, derived } from "svelte/store";
 import { listen, type UnlistenFn } from "@tauri-apps/api/event";
 import type { Library, MediaItem, SearchResult, Genre } from "$lib/api/types";
 import type { SearchOptions } from "$lib/api/bindings";
-import { scopeItemTypes, type SearchScope } from "$lib/utils/searchScope";
+import type { SearchScope } from "$lib/utils/searchScope";
 import { auth } from "./auth";
 
 /**
@@ -227,12 +227,13 @@ function createLibraryStore() {
   /**
    * Search the library, optionally narrowed to a scope.
    *
-   * `scope` is additive and defaults to `all`, which sends no
-   * `includeItemTypes` at all — see scopeItemTypes() for why that differs from
-   * listing every type. Both the online and offline repository paths already
-   * honour the filter.
+   * The scope is sent **opaque**; Rust expands it into Jellyfin item types
+   * (`SearchScope::item_types()`) before the cache and server paths diverge, so
+   * online and offline results filter identically. `all` resolves to no filter
+   * at all — not the union of the other scopes, which would drop People and
+   * folders.
    *
-   * TRACES: UR-049 | DR-065
+   * TRACES: UR-049 | DR-063, DR-065
    */
   async function search(query: string, scope: SearchScope = "all") {
     // Bump the request id for every call (including clears) so any in-flight
@@ -259,10 +260,9 @@ function createLibraryStore() {
       // Phase 1: the command resolves with instant local-cache results. The
       // merged (cache + server) union arrives later via the `search-event`
       // listener above, tagged with this same requestId.
-      const itemTypes = scopeItemTypes(scope);
-      const options: SearchOptions = { limit: 10000 };
-      // Omit the key entirely for the `all` scope rather than sending null.
-      if (itemTypes) options.includeItemTypes = itemTypes;
+      // Send the opaque scope; Rust expands it to item types. The frontend
+      // never names a Jellyfin item type in connection with search.
+      const options: SearchOptions = { limit: 10000, scope };
 
       const result = await Promise.race([
         repo.search(query, options, requestId),

src/lib/stores/librarySearchScope.test.ts

@@ -32,35 +32,43 @@ describe("library.search scoping", () => {
     library.clearSearch();
   });
 
-  it("omits includeItemTypes entirely for the default (all) scope", async () => {
+  // The frontend sends the OPAQUE scope and never names a Jellyfin item type.
+  // Expansion (music → MusicAlbum/MusicArtist/Audio/Playlist) is asserted in
+  // Rust — see `search_scope_tests` in src-tauri/src/repository/types.rs.
+  // Asserting item types here would mean the frontend knows the taxonomy again,
+  // which is the leak docs/specs/scoped-search-boundary.md exists to prevent.
+
+  it("sends the default (all) scope and never an item-type list", async () => {
     await library.search("office");
 
     const options = searchMock.mock.calls[0][1];
+    expect(options.scope).toBe("all");
     expect(options).not.toHaveProperty("includeItemTypes");
     expect(options.limit).toBe(10000);
   });
 
-  it("forwards music item types when scoped to music", async () => {
+  it("sends the opaque scope when scoped to music", async () => {
     await library.search("office", "music");
 
-    expect(searchMock.mock.calls[0][1].includeItemTypes).toEqual([
-      "MusicAlbum",
-      "MusicArtist",
-      "Audio",
-      "Playlist",
-    ]);
+    const options = searchMock.mock.calls[0][1];
+    expect(options.scope).toBe("music");
+    expect(options).not.toHaveProperty("includeItemTypes");
   });
 
-  it("forwards tv item types when scoped to tv", async () => {
+  it("sends the opaque scope when scoped to tv", async () => {
     await library.search("office", "tv");
 
-    expect(searchMock.mock.calls[0][1].includeItemTypes).toEqual(["Series", "Episode"]);
+    const options = searchMock.mock.calls[0][1];
+    expect(options.scope).toBe("tv");
+    expect(options).not.toHaveProperty("includeItemTypes");
   });
 
-  it("forwards movie item types when scoped to movies", async () => {
+  it("sends the opaque scope when scoped to movies", async () => {
     await library.search("office", "movies");
 
-    expect(searchMock.mock.calls[0][1].includeItemTypes).toEqual(["Movie"]);
+    const options = searchMock.mock.calls[0][1];
+    expect(options.scope).toBe("movies");
+    expect(options).not.toHaveProperty("includeItemTypes");
   });
 
   it("stores results and the query on success", async () => {

src/lib/utils/backgroundAudio.test.ts

@@ -0,0 +1,68 @@
+import { describe, it, expect, beforeEach, vi } from "vitest";
+import { setBackgroundAudioEnabled } from "./backgroundAudio";
+
+/**
+ * Bridge-reporting contract for the background-audio toggle.
+ *
+ * TRACES: UR-040 | IR-025, DR-051 | UT-062
+ *
+ * Regression guard for the "screen lock kills video audio" bug: MainActivity
+ * re-ran configureWebViewForMedia() on every onResume, re-calling
+ * addJavascriptInterface over a live page. WebView then served a stale proxy —
+ * `window.AndroidBackgroundAudio` stayed truthy but its methods were gone, so
+ * `setEnabled` threw `TypeError: e.setEnabled is not a function`.
+ *
+ * The old implementation swallowed that with `bridge()?.setEnabled(...)` inside
+ * a try/catch returning void, so the UI showed "armed" while native never got
+ * the flag — and onStop's `if (backgroundAudioEnabled)` guard never dispatched
+ * `jellytau-background`. Audio died the instant the screen locked.
+ *
+ * setBackgroundAudioEnabled must therefore REPORT whether native was actually
+ * reached, so a dead bridge can never masquerade as an armed toggle.
+ */
+describe("setBackgroundAudioEnabled", () => {
+  beforeEach(() => {
+    delete (window as unknown as Record<string, unknown>).AndroidBackgroundAudio;
+    vi.restoreAllMocks();
+  });
+
+  it("reports success when the bridge is present and the call lands", () => {
+    const setEnabled = vi.fn();
+    window.AndroidBackgroundAudio = { setEnabled };
+
+    expect(setBackgroundAudioEnabled(true)).toBe(true);
+    expect(setEnabled).toHaveBeenCalledWith(true);
+  });
+
+  it("reports failure when the bridge object is absent entirely", () => {
+    expect(setBackgroundAudioEnabled(true)).toBe(false);
+  });
+
+  it("reports failure for a stale proxy whose methods are gone", () => {
+    // The exact shape of the bug: object present (so `?.` passes) but the
+    // method is missing after re-injection over a live page.
+    window.AndroidBackgroundAudio = {} as unknown as typeof window.AndroidBackgroundAudio;
+
+    expect(setBackgroundAudioEnabled(true)).toBe(false);
+  });
+
+  it("reports failure when the bridge method throws", () => {
+    window.AndroidBackgroundAudio = {
+      setEnabled: () => {
+        throw new TypeError("e.setEnabled is not a function");
+      },
+    };
+
+    expect(setBackgroundAudioEnabled(true)).toBe(false);
+  });
+
+  it("never throws out to the caller — the toggle must not break the player", () => {
+    window.AndroidBackgroundAudio = {
+      setEnabled: () => {
+        throw new Error("boom");
+      },
+    };
+
+    expect(() => setBackgroundAudioEnabled(false)).not.toThrow();
+  });
+});

src/lib/utils/backgroundAudio.ts

@@ -20,7 +20,6 @@
 
 interface AndroidBackgroundAudioBridge {
   setEnabled(enabled: boolean): void;
-  isSupported(): boolean;
 }
 
 declare global {
@@ -34,25 +33,27 @@ function bridge(): AndroidBackgroundAudioBridge | undefined {
   return window.AndroidBackgroundAudio;
 }
 
-/** Whether background audio is available — used to decide if the toggle renders. */
-export function isBackgroundAudioSupported(): boolean {
-  try {
-    return bridge()?.isSupported() ?? false;
-  } catch (err) {
-    console.warn("[BgAudio] isSupported check failed:", err);
-    return false;
-  }
-}
-
 /**
  * Arm/disarm background-audio mode for the current video. When armed, the native
  * side runs the audio handoff on background instead of entering PiP.
  */
-export function setBackgroundAudioEnabled(enabled: boolean): void {
+export function setBackgroundAudioEnabled(enabled: boolean): boolean {
+  const b = bridge();
+  if (!b) {
+    // The button is gated on platform(), not on this bridge, so it can render
+    // before/without the bridge existing. Silently no-oping here leaves the UI
+    // showing "armed" while native never learns — and the handoff then never
+    // fires on lock. Report it so callers can retry.
+    console.warn("[BgAudio] setEnabled: bridge missing, native NOT armed");
+    return false;
+  }
   try {
-    bridge()?.setEnabled(enabled);
+    b.setEnabled(enabled);
+    console.log("[BgAudio] setEnabled ->", enabled);
+    return true;
   } catch (err) {
     console.warn("[BgAudio] Failed to set enabled:", err);
+    return false;
   }
 }
 

src/lib/utils/searchScope.test.ts

@@ -9,7 +9,6 @@ import {
   resolveSearchScope,
   searchRouteUrl,
   shouldNavigateToSearch,
-  scopeItemTypes,
   type SearchGroupId,
 } from "./searchScope";
 
@@ -62,25 +61,12 @@ describe("resolveSearchScope", () => {
   });
 });
 
-describe("scopeItemTypes", () => {
-  it("omits the key entirely for the all scope", () => {
-    // `all` must send no includeItemTypes — an explicit union would silently
-    // drop types nobody enumerated (Person, folders).
-    expect(scopeItemTypes("all")).toBeUndefined();
-  });
-
-  it("maps each narrow scope to its item types", () => {
-    expect(scopeItemTypes("music")).toEqual(["MusicAlbum", "MusicArtist", "Audio", "Playlist"]);
-    expect(scopeItemTypes("movies")).toEqual(["Movie"]);
-    expect(scopeItemTypes("tv")).toEqual(["Series", "Episode"]);
-  });
-
-  it("returns a fresh array callers cannot mutate into the table", () => {
-    const first = scopeItemTypes("movies")!;
-    first.push("Series");
-    expect(scopeItemTypes("movies")).toEqual(["Movie"]);
-  });
-});
+// NOTE: the former `scopeItemTypes` suite moved to Rust — see
+// `search_scope_tests` in src-tauri/src/repository/types.rs. The scope →
+// item-type expansion is domain vocabulary and is no longer reachable from the
+// frontend, so testing it here would mean re-introducing the leak to test it.
+// The "fresh array" test is gone because `item_types()` returns an owned Vec,
+// making the aliasing bug it guarded structurally impossible.
 
 describe("normalizeGroupOrder", () => {
   it("returns the default for missing or non-array input", () => {

src/lib/utils/searchScope.ts

@@ -8,7 +8,11 @@
 //
 // TRACES: UR-049, UR-050 | DR-063, DR-066, DR-067
 
-export type SearchScope = "all" | "music" | "movies" | "tv";
+// Sourced from Rust via the generated bindings — the backend owns what a scope
+// *means* (which Jellyfin item types it covers). Naming an opaque variant is
+// presentation; knowing its expansion is domain vocabulary and stays in Rust.
+export type { SearchScope } from "$lib/api/bindings";
+import type { SearchScope } from "$lib/api/bindings";
 
 export const SEARCH_SCOPES: readonly SearchScope[] = ["all", "music", "movies", "tv"];
 
@@ -19,29 +23,11 @@ export const SCOPE_LABELS: Record<SearchScope, string> = {
   tv: "TV",
 };
 
-/**
- * Jellyfin item types requested for each scope.
- *
- * `all` is deliberately absent: sending no `includeItemTypes` is *not* the same
- * as sending the union of the lists below — types nobody enumerated here
- * (Person, folders, …) would be filtered out by an explicit list.
- */
-const SCOPE_ITEM_TYPES: Record<Exclude<SearchScope, "all">, string[]> = {
-  music: ["MusicAlbum", "MusicArtist", "Audio", "Playlist"],
-  movies: ["Movie"],
-  tv: ["Series", "Episode"],
-};
-
-/**
- * Item types to send with a scoped search, or `undefined` for the `all` scope
- * so the caller omits the key entirely.
- *
- * TRACES: UR-049 | DR-063
- */
-export function scopeItemTypes(scope: SearchScope): string[] | undefined {
-  if (scope === "all") return undefined;
-  return [...SCOPE_ITEM_TYPES[scope]];
-}
+// NOTE: the scope → Jellyfin item-type mapping deliberately does NOT live here.
+// It is domain vocabulary and lives in Rust (`SearchScope::item_types()` in
+// repository/types.rs); the frontend sends the opaque scope and the backend
+// expands it. Re-introducing a `{ music: ["MusicAlbum", …] }` table in this file
+// is the boundary leak documented in docs/specs/scoped-search-boundary.md.
 
 /**
  * Resolve the scope a search started from a given route should default to.

vitest.config.ts

@@ -8,7 +8,9 @@ export default defineConfig({
     globals: true,
     environment: "jsdom",
     setupFiles: ["./src/test/setup-globals.ts", "./src/test/setup.ts"],
-    include: ["src/**/*.{test,spec}.{js,ts}"],
+    // `scripts/` is included so build tooling (the traceability coverage
+    // engine) is covered by the normal suite rather than only by CI.
+    include: ["src/**/*.{test,spec}.{js,ts}", "scripts/**/*.{test,spec}.{js,ts}"],
     coverage: {
       provider: "v8",
       reporter: ["text", "json", "html"],