Move playback-related media state into shared model types and make the player consume a single PlayableMedia object instead of separately loading MediaItems, track preferences, resume positions, and media segments.
This updates PlayableMediaRepository to return playable media bundles, seeds the player playlist with the current item, keeps next-up entries in the same model, restores resume/segment handling, and fixes current queue highlighting.
The change also moves track preference models into core-model, centralizes Jellyfin BaseItemDto conversion, removes placeholder movie audio/subtitle fields, bumps the offline Room schema, and updates mobile/TV queue UI code for the playlist model.
Verification:
./gradlew --no-daemon :core-model:compileDebugKotlin :core:compileDebugKotlin :data:compileDebugKotlin :app:compileDebugKotlin
Integrate `navigation3` into `AppScreen` to manage tab transitions and
backstack state. Replaced manual tab state management with `NavDisplay`
and `NavBackStack`, and added horizontal slide animations for switching
between Home, Libraries, and Downloads screens.
Consolidates specific media selection callbacks (`onMovieSelected`, `onSeriesSelected`, `onEpisodeSelected`) into a single `onMediaSelected` handler that accepts a `MediaUiModel`. This simplifies the interface between the ViewModel and UI components across both mobile and TV screens, moving the type-checking logic into `AppViewModel`.
Introduce a `FocusableItem` interface to unify media item properties (ID, type, text, and images) across `ContinueWatchingItem`, `NextUpItem`, and `PosterItem`.
Key changes:
- Implement automatic initial focus on the first available item in `TvHomeContent`.
- Add `onMediaFocused` callbacks to TV sections and cards to track active items.
- Standardize image URL generation and metadata access in home models.
- Clean up unused previews in `HomeScreen`.
- Add UI tests for TV home content focus behavior.
Adjusts the `HorizontalPager` to use a fixed page size and consistent horizontal padding. This ensures the suggestion cards have a predictable width on wider screens.
