fix(player): stop letting item metadata language override the audio track

The audio ladder still carried a per-item language tier between the
server's selected stream and the account preference. For Jellyfin and
Emby the value mapped to it was `PreferredMetadataLanguage`, which is the
library's metadata-scraping language - it inherits from the parent, the
library options, or the server config and says nothing about playback -
so on any source whose selected/default stream did not map to a native
track it silently picked audio in the scraping language instead of the
user's preferred one. Plex's item-level `audioLanguage` reached the same
tier, after 2dfebf32b and 7ae293631 had already settled that the server
folds every preference level into the stream `selected` flags.

Drop the tier and the plumbing that only fed it:
TrackSelectionPriority.perMedia, MediaItem.audioLanguage and
subtitleLanguage, PlexMetadataDto.audioLanguage/subtitleLanguage/
subtitleMode, and the Jellyfin PreferredMetadataLanguage mapping. The
order is now carried selection, server-selected or default source
stream, account preference, native default. Persisted cache entries
holding the old keys decode unchanged.

lib/media/media_item.dart

@@ -177,8 +177,6 @@ sealed class MediaItem with _$MediaItem {
     @JsonKey(fromJson: _mediaItemVersionsFromJson) List<MediaVersion>? mediaVersions,
     String? libraryId,
     String? libraryTitle,
-    String? audioLanguage,
-    String? subtitleLanguage,
     String? trailerKey,
     @JsonKey(fromJson: flexibleInt) int? playlistItemId,
     @JsonKey(fromJson: flexibleInt) int? playQueueItemId,
@@ -266,7 +264,6 @@ sealed class MediaItem with _$MediaItem {
     @JsonKey(fromJson: _mediaItemVersionsFromJson) List<MediaVersion>? mediaVersions,
     String? libraryId,
     String? libraryTitle,
-    String? audioLanguage,
 
     /// Jellyfin playlist entry id used by playlist write endpoints.
     String? playlistItemId,

lib/media/media_item.g.dart

@@ -67,8 +67,6 @@ PlexMediaItem _$PlexMediaItemFromJson(Map<String, dynamic> json) =>
       mediaVersions: _mediaItemVersionsFromJson(json['mediaVersions']),
       libraryId: json['libraryId'] as String?,
       libraryTitle: json['libraryTitle'] as String?,
-      audioLanguage: json['audioLanguage'] as String?,
-      subtitleLanguage: json['subtitleLanguage'] as String?,
       trailerKey: json['trailerKey'] as String?,
       playlistItemId: flexibleInt(json['playlistItemId']),
       playQueueItemId: flexibleInt(json['playQueueItemId']),
@@ -135,8 +133,6 @@ Map<String, dynamic> _$PlexMediaItemToJson(PlexMediaItem instance) =>
       'mediaVersions': ?instance.mediaVersions?.map((e) => e.toJson()).toList(),
       'libraryId': ?instance.libraryId,
       'libraryTitle': ?instance.libraryTitle,
-      'audioLanguage': ?instance.audioLanguage,
-      'subtitleLanguage': ?instance.subtitleLanguage,
       'trailerKey': ?instance.trailerKey,
       'playlistItemId': ?instance.playlistItemId,
       'playQueueItemId': ?instance.playQueueItemId,
@@ -207,7 +203,6 @@ JellyfinMediaItem _$JellyfinMediaItemFromJson(Map<String, dynamic> json) =>
       mediaVersions: _mediaItemVersionsFromJson(json['mediaVersions']),
       libraryId: json['libraryId'] as String?,
       libraryTitle: json['libraryTitle'] as String?,
-      audioLanguage: json['audioLanguage'] as String?,
       playlistItemId: json['playlistItemId'] as String?,
       serverId: json['serverId'] as String?,
       serverName: json['serverName'] as String?,
@@ -270,7 +265,6 @@ Map<String, dynamic> _$JellyfinMediaItemToJson(JellyfinMediaItem instance) =>
       'mediaVersions': ?instance.mediaVersions?.map((e) => e.toJson()).toList(),
       'libraryId': ?instance.libraryId,
       'libraryTitle': ?instance.libraryTitle,
-      'audioLanguage': ?instance.audioLanguage,
       'playlistItemId': ?instance.playlistItemId,
       'serverId': ?instance.serverId,
       'serverName': ?instance.serverName,

lib/services/jellyfin_mappers.dart

@@ -292,7 +292,6 @@ class JellyfinMappers {
       // stamps — scoped search, the Ancestors lookup, caller passthrough.
       libraryId: null,
       libraryTitle: null,
-      audioLanguage: item['PreferredMetadataLanguage'] as String?,
       // Only present when the item came out of `/Playlists/{id}/Items`; the
       // playlist write endpoints address rows by this id, not the media id.
       playlistItemId: item['PlaylistItemId'] as String?,

lib/services/plex_mappers.dart

@@ -650,10 +650,6 @@ class PlexMetadataDto {
   final List<String>? format;
   @JsonKey(name: 'Subformat', fromJson: _tagListFromJson, includeToJson: false)
   final List<String>? subformat;
-  final String? audioLanguage;
-  final String? subtitleLanguage;
-  @JsonKey(fromJson: flexibleInt)
-  final int? subtitleMode;
   @JsonKey(fromJson: flexibleInt)
   final int? playlistItemID;
   @JsonKey(fromJson: flexibleInt)
@@ -733,9 +729,6 @@ class PlexMetadataDto {
     this.mood,
     this.format,
     this.subformat,
-    this.audioLanguage,
-    this.subtitleLanguage,
-    this.subtitleMode,
     this.playlistItemID,
     this.playQueueItemID,
     this.librarySectionID,
@@ -860,9 +853,6 @@ class PlexMetadataDto {
     List<String>? mood,
     List<String>? format,
     List<String>? subformat,
-    String? audioLanguage,
-    String? subtitleLanguage,
-    int? subtitleMode,
     int? playlistItemID,
     int? playQueueItemID,
     int? librarySectionID,
@@ -934,9 +924,6 @@ class PlexMetadataDto {
       mood: mood ?? this.mood,
       format: format ?? this.format,
       subformat: subformat ?? this.subformat,
-      audioLanguage: audioLanguage ?? this.audioLanguage,
-      subtitleLanguage: subtitleLanguage ?? this.subtitleLanguage,
-      subtitleMode: subtitleMode ?? this.subtitleMode,
       playlistItemID: playlistItemID ?? this.playlistItemID,
       playQueueItemID: playQueueItemID ?? this.playQueueItemID,
       librarySectionID: librarySectionID ?? this.librarySectionID,
@@ -1141,8 +1128,6 @@ class PlexMappers {
       mediaVersions: dto.mediaVersions?.map(mediaVersion).toList(),
       libraryId: dto.librarySectionID?.toString(),
       libraryTitle: dto.librarySectionTitle,
-      audioLanguage: dto.audioLanguage,
-      subtitleLanguage: dto.subtitleLanguage,
       trailerKey: dto.primaryExtraKey,
       playlistItemId: dto.playlistItemID,
       playQueueItemId: dto.playQueueItemID,

lib/services/plex_mappers.g.dart

@@ -146,9 +146,6 @@ PlexMetadataDto _$PlexMetadataDtoFromJson(Map<String, dynamic> json) =>
       mood: _tagListFromJson(json['Mood']),
       format: _tagListFromJson(json['Format']),
       subformat: _tagListFromJson(json['Subformat']),
-      audioLanguage: json['audioLanguage'] as String?,
-      subtitleLanguage: json['subtitleLanguage'] as String?,
-      subtitleMode: flexibleInt(json['subtitleMode']),
       playlistItemID: flexibleInt(json['playlistItemID']),
       playQueueItemID: flexibleInt(json['playQueueItemID']),
       librarySectionID: flexibleInt(json['librarySectionID']),
@@ -206,9 +203,6 @@ Map<String, dynamic> _$PlexMetadataDtoToJson(PlexMetadataDto instance) =>
       'viewedLeafCount': ?instance.viewedLeafCount,
       'childCount': ?instance.childCount,
       'imdbRatingCount': ?instance.imdbRatingCount,
-      'audioLanguage': ?instance.audioLanguage,
-      'subtitleLanguage': ?instance.subtitleLanguage,
-      'subtitleMode': ?instance.subtitleMode,
       'playlistItemID': ?instance.playlistItemID,
       'playQueueItemID': ?instance.playQueueItemID,
       'librarySectionID': ?instance.librarySectionID,

lib/services/track_selection_service.dart

@@ -661,14 +661,16 @@ bool _titlesMatch(String? mpvTitle, String? plexTitle, String? plexDisplayTitle)
 
 int _mediaTrackStreamIndex(int id, int? index) => index ?? id;
 
-/// Priority levels for track selection
+/// Priority levels for track selection. Per-item language overrides are not a
+/// level: every backend folds them into the source's selected/default stream,
+/// so an item-level language would only ever override the account preference
+/// with something the server had already rejected.
 enum TrackSelectionPriority {
   navigation, // Priority 1: User's manual selection from previous episode
   serverSelected, // Priority 2: server's pre-selected track
-  perMedia, // Priority 3: Per-media language preference
-  profile, // Priority 4: User profile preferences
-  defaultTrack, // Priority 5: Default or first track
-  off, // Priority 6: Subtitles off (subtitle only)
+  profile, // Priority 3: User profile preferences
+  defaultTrack, // Priority 4: Default or first track
+  off, // Priority 5: Subtitles off (subtitle only)
 }
 
 /// Result of track selection including the selected track and which priority was used
@@ -680,7 +682,7 @@ class TrackSelectionResult<T> {
 }
 
 /// Service for selecting and applying audio and subtitle tracks based on
-/// preferences, user profiles, and per-media settings.
+/// carried selections, server-selected streams, and account preferences.
 class TrackSelectionService {
   final Player? player;
   final MediaServerUserProfile? profileSettings;
@@ -948,9 +950,8 @@ class TrackSelectionService {
   /// Select the best audio track based on priority:
   /// Priority 1: Preferred track from navigation
   /// Priority 2: Server-selected track from media info
-  /// Priority 3: Per-media language preference
-  /// Priority 4: User profile preferences
-  /// Priority 5: Default or first track
+  /// Priority 3: User profile preferences
+  /// Priority 4: Default or first track
   TrackSelectionResult<AudioTrack>? selectAudioTrack(
     List<AudioTrack> availableTracks,
     AudioTrack? preferredAudioTrack,
@@ -1021,18 +1022,7 @@ class TrackSelectionService {
       }
     }
 
-    // Priority 3: Try per-media language preference
-    if (metadata.audioLanguage != null) {
-      final matchedTrack = availableTracks.firstWhere(
-        (track) => languageMatches(track.language, metadata.audioLanguage),
-        orElse: () => availableTracks.first,
-      );
-      if (languageMatches(matchedTrack.language, metadata.audioLanguage)) {
-        return TrackSelectionResult(matchedTrack, TrackSelectionPriority.perMedia);
-      }
-    }
-
-    // Priority 4: Try user profile preferences
+    // Priority 3: Try user profile preferences
     if (profileSettings != null) {
       trackToSelect = findAudioTrackByProfile(availableTracks, profileSettings!);
       if (trackToSelect != null) {
@@ -1040,7 +1030,7 @@ class TrackSelectionService {
       }
     }
 
-    // Priority 5: Use default or first track
+    // Priority 4: Use default or first track
     trackToSelect = availableTracks.firstWhere((t) => t.isDefault, orElse: () => availableTracks.first);
     return TrackSelectionResult(trackToSelect, TrackSelectionPriority.defaultTrack);
   }

test/media/media_item_test.dart

@@ -483,7 +483,6 @@ void main() {
           MediaRatingSource(source: 'rottenTomatoesCritic', value: 9.4),
           MediaRatingSource(source: 'imdb', value: 8.9, votes: 1200),
         ],
-        subtitleLanguage: 'eng',
         trailerKey: '/library/metadata/1',
         playlistItemId: 42,
         playQueueItemId: 7,
@@ -495,7 +494,6 @@ void main() {
       expect(copy.editionTitle, 'Director Cut');
       expect(copy.ratings?.map((rating) => rating.source), ['rottenTomatoesCritic', 'imdb']);
       expect(copy.ratings?.last.votes, 1200);
-      expect(copy.subtitleLanguage, 'eng');
       expect(copy.trailerKey, '/library/metadata/1');
       expect(copy.playlistItemId, 42);
       expect(copy.playQueueItemId, 7);
@@ -547,7 +545,6 @@ void main() {
             parts: [MediaPart(id: 'part1', streamPath: '/stream', sizeBytes: 1000)],
           ),
         ],
-        subtitleLanguage: 'eng',
         trailerKey: '/trailer',
         playlistItemId: 4,
         playQueueItemId: 5,
@@ -567,7 +564,6 @@ void main() {
       expect(plex.genres, ['Drama']);
       expect(plex.roles?.single.tag, 'Actor');
       expect(plex.mediaVersions?.single.parts.single.streamPath, '/stream');
-      expect(plex.subtitleLanguage, 'eng');
       expect(plex.trailerKey, '/trailer');
       expect(plex.playlistItemId, 4);
       expect(plex.playQueueItemId, 5);

test/services/track_selection_service_test.dart

@@ -14,14 +14,8 @@ import '../test_helpers/media_items.dart';
 // including fallback and ambiguity rules. `selectAndApplyTracks` is excluded
 // because it requires a real Player and SettingsService singleton.
 
-MediaItem _meta({MediaBackend backend = MediaBackend.plex, String? audioLanguage, String? subtitleLanguage}) =>
-    testMediaItem(
-      id: 'rk1',
-      backend: backend,
-      kind: MediaKind.movie,
-      audioLanguage: audioLanguage,
-      subtitleLanguage: subtitleLanguage,
-    );
+MediaItem _meta({MediaBackend backend = MediaBackend.plex}) =>
+    testMediaItem(id: 'rk1', backend: backend, kind: MediaKind.movie);
 
 AccountPreferences _profile({
   bool autoSelectAudio = true,
@@ -373,15 +367,7 @@ void main() {
       expect(result.track.language, 'fre');
     });
 
-    test('Priority 3: per-media audioLanguage from metadata', () {
-      final tracks = [_audio('A', lang: 'eng'), _audio('B', lang: 'fre')];
-      final result = _svc(metadata: _meta(audioLanguage: 'fre')).selectAudioTrack(tracks, null);
-      expect(result, isNotNull);
-      expect(result!.priority, TrackSelectionPriority.perMedia);
-      expect(result.track.language, 'fre');
-    });
-
-    test('Priority 4: user profile when nothing higher matches', () {
+    test('Priority 3: user profile when nothing higher matches', () {
       final tracks = [_audio('A', lang: 'eng'), _audio('B', lang: 'fre')];
       final profile = _profile(defaultAudioLanguage: 'eng');
       final result = _svc(profile: profile).selectAudioTrack(tracks, null);
@@ -390,7 +376,7 @@ void main() {
       expect(result.track.language, 'eng');
     });
 
-    test('Priority 5: default-flagged track as last resort', () {
+    test('Priority 4: default-flagged track as last resort', () {
       final tracks = [_audio('A', lang: 'eng'), _audio('B', lang: 'fre', isDefault: true)];
       final result = _svc().selectAudioTrack(tracks, null);
       expect(result, isNotNull);
@@ -398,7 +384,7 @@ void main() {
       expect(result.track.id, 'B');
     });
 
-    test('Priority 5: first track when none flagged default', () {
+    test('Priority 4: first track when none flagged default', () {
       final tracks = [_audio('A', lang: 'eng'), _audio('B', lang: 'fre')];
       final result = _svc().selectAudioTrack(tracks, null);
       expect(result, isNotNull);
@@ -408,7 +394,7 @@ void main() {
 
     test('preferred mismatch falls through to lower priority', () {
       // preferred has a language that is NOT in the available tracks — Priority 1
-      // misses; Priority 5 picks the first track.
+      // misses; Priority 4 picks the first track.
       final tracks = [_audio('A', lang: 'eng'), _audio('B', lang: 'fre')];
       final result = _svc().selectAudioTrack(tracks, _audio('Z', lang: 'jpn'));
       expect(result, isNotNull);

test/test_helpers/media_items.dart

@@ -63,8 +63,6 @@ MediaItem testMediaItem({
   List<MediaVersion>? mediaVersions,
   String? libraryId,
   String? libraryTitle,
-  String? audioLanguage,
-  String? subtitleLanguage,
   String? serverId,
   String? serverName,
   String? backendFolderKey,
@@ -129,8 +127,6 @@ MediaItem testMediaItem({
       mediaVersions: mediaVersions,
       libraryId: libraryId,
       libraryTitle: libraryTitle,
-      audioLanguage: audioLanguage,
-      subtitleLanguage: subtitleLanguage,
       serverId: serverId,
       serverName: serverName,
       backendFolderKey: backendFolderKey,
@@ -190,7 +186,6 @@ MediaItem testMediaItem({
       mediaVersions: mediaVersions,
       libraryId: libraryId,
       libraryTitle: libraryTitle,
-      audioLanguage: audioLanguage,
       serverId: serverId,
       serverName: serverName,
       backendFolderKey: backendFolderKey,