fix(trackers): preserve Plex library context

lib/utils/episode_collection.dart

@@ -18,8 +18,9 @@ Future<void> collectEpisodesForShow(
   String showRatingKey, {
   required bool unwatchedOnly,
   required List<MediaItem> out,
+  MediaItem? fallback,
 }) {
-  return _collectPlayable(client, showRatingKey, unwatchedOnly: unwatchedOnly, out: out);
+  return _collectPlayable(client, showRatingKey, unwatchedOnly: unwatchedOnly, out: out, fallback: fallback);
 }
 
 /// Collect every episode of a single season into [out] via the same
@@ -30,8 +31,9 @@ Future<void> collectEpisodesForSeason(
   String seasonRatingKey, {
   required bool unwatchedOnly,
   required List<MediaItem> out,
+  MediaItem? fallback,
 }) {
-  return _collectPlayable(client, seasonRatingKey, unwatchedOnly: unwatchedOnly, out: out);
+  return _collectPlayable(client, seasonRatingKey, unwatchedOnly: unwatchedOnly, out: out, fallback: fallback);
 }
 
 Future<void> _collectPlayable(
@@ -39,11 +41,22 @@ Future<void> _collectPlayable(
   String parentId, {
   required bool unwatchedOnly,
   required List<MediaItem> out,
+  MediaItem? fallback,
 }) async {
   final leaves = await client.fetchPlayableDescendants(parentId);
   for (final ep in leaves) {
     if (ep.kind != MediaKind.episode) continue;
     if (unwatchedOnly && ep.isWatched && !ep.hasActiveProgress) continue;
-    out.add(ep);
+    out.add(_withFallbackLibrary(ep, fallback));
   }
 }
+
+MediaItem _withFallbackLibrary(MediaItem item, MediaItem? fallback) {
+  if (fallback == null) return item;
+  return item.copyWith(
+    serverId: item.serverId ?? fallback.serverId,
+    serverName: item.serverName ?? fallback.serverName,
+    libraryId: item.libraryId ?? fallback.libraryId,
+    libraryTitle: item.libraryTitle ?? fallback.libraryTitle,
+  );
+}

lib/utils/media_navigation_helper.dart

@@ -124,6 +124,8 @@ Future<MediaNavigationResult> navigateToMediaItem(
           title: mi.grandparentTitle ?? mi.parentTitle ?? mi.displayTitle,
           thumbPath: mi.grandparentThumbPath ?? mi.parentThumbPath,
           artPath: mi.grandparentArtPath,
+          libraryId: mi.libraryId,
+          libraryTitle: mi.libraryTitle,
           serverId: mi.serverId,
           serverName: mi.serverName,
         );

lib/utils/plex_cache_parser.dart

@@ -4,9 +4,13 @@
 class PlexCacheParser {
   PlexCacheParser._();
 
+  static Map<String, dynamic>? extractMediaContainer(Map<String, dynamic>? cached) {
+    final container = cached?['MediaContainer'];
+    return container is Map<String, dynamic> ? container : null;
+  }
+
   static List<dynamic>? extractMetadataList(Map<String, dynamic>? cached) {
-    if (cached == null) return null;
-    return cached['MediaContainer']?['Metadata'] as List?;
+    return extractMediaContainer(cached)?['Metadata'] as List?;
   }
 
   static Map<String, dynamic>? extractFirstMetadata(Map<String, dynamic>? cached) {

lib/utils/plex_library_section_utils.dart

@@ -0,0 +1,27 @@
+import 'json_utils.dart';
+
+final RegExp plexLibrarySectionPathPattern = RegExp(r'/(?:library|hubs)/sections/(\d+)');
+
+int? plexLibrarySectionIdFromJson(Map<String, dynamic>? json) {
+  if (json == null) return null;
+  final direct = flexibleInt(json['librarySectionID']) ?? flexibleInt(json['targetLibrarySectionID']);
+  if (direct != null) return direct;
+
+  for (final key in const ['librarySectionKey', 'key', 'hubKey']) {
+    final parsed = plexLibrarySectionIdFromString(json[key]?.toString());
+    if (parsed != null) return parsed;
+  }
+  return null;
+}
+
+int? plexLibrarySectionIdFromString(String? value) {
+  if (value == null || value == 'shared') return null;
+  final direct = int.tryParse(value);
+  if (direct != null) return direct;
+  final match = plexLibrarySectionPathPattern.firstMatch(value);
+  return match == null ? null : int.tryParse(match.group(1)!);
+}
+
+String? plexLibrarySectionTitleFromJson(Map<String, dynamic>? json) {
+  return json?['librarySectionTitle']?.toString();
+}

lib/utils/watch_state_notifier.dart

@@ -63,7 +63,8 @@ class WatchStateEvent with HierarchicalEventMixin {
   }) : globalKey = buildGlobalKey(serverId, itemId);
 
   /// `serverId:librarySectionID`, matching [MediaLibrary.globalKey]. Null when
-  /// the library section is unknown.
+  /// the library section is unknown; tracker filters treat unknown as allowed
+  /// only when no filter is configured.
   String? get librarySectionGlobalKey => librarySectionID != null ? buildGlobalKey(serverId, librarySectionID!) : null;
 
   @override