fix(player): make the video seek bar work by touch (DR-099)

On Android, dragging or tapping the progress bar moved the thumb but
playback stayed where it was. Two separate defects, both touch-only,
which is why the mouse-driven scrub tests never caught either.

1. Gesture hijack. DR-098 taught handleTouchStart to ignore touches that
   land on a control, but handleTouchMove kept running. It measures
   against touchStartX/Y, which that early return leaves at the PREVIOUS
   gesture's values, so a seek-bar drag produced a huge bogus vertical
   delta: read as a brightness swipe, it 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 unlatched — re-checking the move target cannot
   recover a start point that was never recorded.

2. 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, so the thumb moved to the tapped position and no seek
   ever ran. touchend/mouseup now commit too; `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.

Tests drive the slider with real touch events (UT-089, UT-090) and fail
against the pre-fix component.

docs/requirements.md

@@ -249,6 +249,7 @@ Internal architecture, components, and application logic.
 | 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 |
@@ -416,6 +417,8 @@ Internal architecture, components, and application logic.
 | 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