fix(android): clear the system bars and display cutout (UR-066)

The bottom nav rendered under the Android navigation bar, and full-screen
playback controls spilled into unusable screen edges. It looked device-specific
(Motorola bad, Fairphone fine) but every device was equally unpadded — only the
intrusion differed: a tall opaque 3-button bar swallows the nav, a thin
translucent gesture pill overlaps harmlessly.

None of the app's safe-area handling was ever active, for two independent
reasons:

  1. app.html had no `viewport-fit=cover`, so every `env(safe-area-inset-*)`
     resolved to 0px — the padding in app.css and BottomUi was a no-op.
  2. Android WebView maps only the *display cutout* into `env()`; the status bar
     and navigation bar are never reported. With enableEdgeToEdge() and
     targetSdk 36 (enforced from 35, opt-out ignored from 36) the WebView always
     spans them, so CSS could not learn about them by any route.

WindowInsetsBridge now reads `systemBars() | displayCutout()` and publishes
`--jt-inset-*` CSS custom properties, both pushed on every inset change
(rotation, nav-mode switch, PiP) and pullable via `AndroidInsets.get()` — the
pull is required because the first inset pass lands before the document exists
and a page load wipes the pushed inline style. app.css folds them with `env()`
via `max()` into `--safe-*`, the only thing components may pad from.

Exactly one element owns each edge: the shell takes top/left/right, BottomUi
takes bottom (inside its surface box, so the colour extends behind the gesture
bar), and shellReservesBottomInset hands bottom back to the shell on routes with
no bottom UI. The full-screen players inset their control layers only, leaving
video and artwork edge-to-edge.

The theme's `fitsSystemWindows=true` claimed the opposite of what actually
happened — overridden at runtime, ignored at this target SDK — and is removed.

Also converts six nested `h-screen`/`min-h-screen` boxes to `h-full`: the shell
is `h-screen` *and* inset-padded, so its content box is `100vh - safe-top` and
any nested 100vh box overflows by exactly the inset (the library column would
have clipped its own BottomUi). A test guards against reintroduction.

docs/requirements.md

@@ -75,6 +75,7 @@ For a narrative overview of the system design, see
 | UR-062 | Opening a TV series lands the viewer **where they are in it**, not at season 1: the series page scrolls the current season into view and highlights the current episode, and the hero button opens that episode (labelled `Resume S2E4` / `Play S1E1`). "Current" means the episode in progress, else the server's Next Up for that series, else the first unwatched episode, else the first — resolved by the backend so it also works offline. A season is **never a page of its own**: every route that names a season lands on the series with that season in view, so the episodes of all seasons are always one continuous scrollable list | High | Done |
 | UR-063 | Each video library is **one page**, not three. Browsing (hero, Continue Watching, Next Up, Recently Added, genre rows), the full title grid, and the genre browser are tabs of `/library/tv` and `/library/movies` rather than separate routes with inconsistent names (`/library/tv/shows` vs `/library/movies/all`, `/library/shows/genres` vs `/library/movies/genres`). The old routes redirect so existing links keep working | Medium | Done |
 | UR-064 | Watch history can be **erased**, per series and per season, from the series page. Clearing marks every episode inside unwatched and clears resume positions, so the show returns to "never watched" and reopens on its premiere. It asks for confirmation first (it cannot be undone) and requires a connection to the server, since history cleared only locally would be undone by the next sync | Medium | Done |
+| UR-066 | The app's own chrome stays clear of the device's system chrome. On Android the bottom navigation sits above the navigation/gesture bar instead of underneath it, the header clears the status bar, and full-screen video and audio playback keep their controls inside the usable screen — clear of the gesture bar and, in landscape, of the display notch. This must hold across navigation modes (gesture and 3-button) and rotation, not only on the handsets it happened to be tested on | High | Done |
 
 ---
 
@@ -115,6 +116,7 @@ External system integrations and platform-specific implementations.
 | IR-027 | Jellyfin `/System/Info/Public` reachability probe used as an offline→online recovery detector | API | UR-043 | Done |
 | IR-028 | Jellyfin/LMS SyncGroups API client (list, create, join, unsync, dissolve sync groups) | API | UR-046 | Done |
 | IR-029 | Android `ConnectivityManager`/`NetworkCapabilities` transport probe with a `NetworkCallback` change subscription, surfaced to the frontend via the `AndroidNetworkType` JS bridge and the `jellytau-network-changed` WebView event (requires `ACCESS_NETWORK_STATE`) | Platform | UR-053 | Done (pending device verification) |
+| IR-031 | Android `WindowInsets` bridge: an `OnApplyWindowInsetsListener` on the decor view reports `systemBars() | displayCutout()` in CSS pixels, pushed into the WebView as `jt-inset` CSS custom properties plus a `jellytau-insets-changed` event, and pullable via the `AndroidInsets` JS bridge | Platform | UR-066 | Done (pending device verification) |
 
 ### 2.2 Jellyfin API Requirements
 
@@ -264,6 +266,7 @@ Internal architecture, components, and application logic.
 | DR-105 | Video library routes collapse to one per library. `/library/tv` and `/library/movies` render browse / all-titles / genres as in-page tabs driven by `?view=`, omitted for the default `browse` (the convention `searchRouteUrl` already uses for the `all` scope); `resolveLibraryView` is pure and unit-tested. The four legacy routes become redirect-only `+page.ts` loads rather than deletions, because `GenreTags` links to them and users have them in history; `resolveSearchScope` keeps its `/library/shows` branch for the same reason. The "Browse" tile grid at the bottom of both landing pages is removed — it was a second navigation affordance to the same destinations the carousels' "Show all" links already reach | UI | UR-063 | Done |
 | DR-106 | Erasing watch history goes through the repository, not the local cache: `clear_watch_history(item_id)` maps to Jellyfin's `DELETE /Users/{userId}/PlayedItems/{itemId}`, which clears the played flag *and* zeroes the resume position, and which the server applies recursively to a folder — so one call handles a whole series or season. `OfflineRepository` returns `RepoError::Offline` rather than clearing locally, because history diverged only on the device would be silently undone by the next sync; the button disables itself while the server is unreachable. `ClearHistoryButton` is shared by the series hero and each `SeasonSection` header, confirms before acting (there is no undo), and reloads the page on success so the recomputed current episode — the premiere, for a fully cleared series — is what the viewer sees | Repository | UR-064 | Done |
 | DR-107 | Seasons on the series page are collapsible, and **only the current season is expanded** on load — the one holding the episode DR-101 resolved. A show with ten seasons otherwise renders every episode of every season at once, burying the one episode the viewer came for under hundreds of rows. Expansion state is per season and pure (`initialExpandedSeasons` in `seriesNavigation.ts`): the current season, or the first season when there is no current episode, so a never-watched show still opens on season 1 rather than fully collapsed. A `?episode=` deep link expands that episode's season too. Toggling is local and not persisted — it is a reading position, not a preference | UI | UR-062 | Done |
+| DR-112 | Safe-area insets come from **native**, not from `env()` alone. `env(safe-area-inset-*)` is 0px without `viewport-fit=cover` (missing from `app.html`, so every safe-area rule in the app was already a no-op), and even with it Android WebView maps only the *display cutout* — never the status bar or navigation bar. Since `enableEdgeToEdge()` plus `targetSdk 36` make edge-to-edge unconditional, the WebView always spans the system bars, so CSS could not learn about them by any route. `WindowInsetsBridge` reads the real insets and publishes `jt-inset` custom properties; `app.css` folds them with `env()` via `max()` into `--safe-*`, which is the only thing components may pad from. Ownership is exactly one element per edge: the app shell takes top/left/right, and BottomUi takes bottom wherever it renders (`shellReservesBottomInset` hands it back to the shell on routes with no bottom UI) so the padding sits inside BottomUi's surface box and the colour extends behind the gesture bar. The full-screen players inset their control layers only, leaving video and artwork edge-to-edge. The theme's `fitsSystemWindows=true` — which claimed the opposite and was overridden at runtime and ignored at this target SDK — is removed | UI | UR-066 | 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 |
 
 ---
@@ -337,6 +340,7 @@ Internal architecture, components, and application logic.
 | UR-062 | - | DR-101, DR-102, DR-103, DR-104, DR-107 |
 | UR-063 | - | DR-105 |
 | UR-064 | - | DR-106 |
+| UR-066 | IR-031 | DR-112 |
 
 ---
 
@@ -436,6 +440,11 @@ Internal architecture, components, and application logic.
 | 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 |
 | UT-092 | `shouldReuseActivePlayback` reuses backend playback for an already-loaded audio track but never for video, and never when an explicit start position or a next-episode restart was requested | DR-100 | Done |
 | UT-093 | `resolvePlayerSurface` returns `video` only with a stream URL, `pending` for video whose stream URL is still missing (never `audio`), and `audio` for audio content | DR-100 | Done |
+| UT-094 | `parseNativeInsets` accepts the bridge's JSON or a decoded object, and coerces missing/negative/non-finite edges to 0 rather than emitting `NaNpx` (which would invalidate the whole padding declaration) | DR-112 | Done |
+| UT-095 | `safeAreaCssVars`/`applySafeAreaInsets` emit px-suffixed `jt-inset` custom properties for all four edges | DR-112 | Done |
+| UT-096 | `readNativeInsets` returns null with no bridge and survives a stale WebView proxy (missing or throwing `get`) instead of throwing out of layout init | IR-031, DR-112 | Done |
+| UT-097 | `initSafeArea` primes the document on start, re-applies on `jellytau-insets-changed` (rotation, nav-mode switch), unsubscribes on teardown, and writes nothing without a bridge so `env()` still wins on iOS/desktop | IR-031, DR-112 | Done |
+| UT-098 | `shellReservesBottomInset` gives the bottom inset to BottomUi wherever one renders and to the app shell only on routes without one, so the gesture bar is never ignored nor double-padded | DR-112 | Done |
 
 ### Integration Tests