fix(tv): focus flattened episode rows

close #1081

lib/screens/media_detail_screen.dart

@@ -3211,8 +3211,13 @@ class _MediaDetailScreenState extends State<MediaDetailScreen>
   }
 
   String? _tvDetailInitialHubId(MediaItem metadata) {
-    if (!metadata.isShow || _showEpisodesDirectly || _seasons.isEmpty) return null;
-    return '$_tvDetailSeasonHubIdPrefix$_selectedSeasonIndex';
+    if (metadata.isShow && !_showEpisodesDirectly && _seasons.isNotEmpty) {
+      return '$_tvDetailSeasonHubIdPrefix$_selectedSeasonIndex';
+    }
+    if ((metadata.isShow && _showEpisodesDirectly) || metadata.isSeason) {
+      return 'detail_episodes';
+    }
+    return null;
   }
 
   String? _tvDetailInitialItemId(MediaItem metadata) {

test/widgets/tv_browse_rail_test.dart

@@ -201,6 +201,48 @@ void main() {
     expect(activeHubIds.last, 'detail_season_1');
   });
 
+  testWidgets('selects preferred hub after an earlier update could not find it', (tester) async {
+    final activeHubIds = <String>[];
+
+    Widget buildRail(List<MediaHub> hubs, {String? initialHubId}) {
+      final serverManager = MultiServerManager();
+      return ChangeNotifierProvider<MultiServerProvider>(
+        create: (_) => MultiServerProvider(serverManager, DataAggregationService(serverManager)),
+        child: MaterialApp(
+          theme: monoTheme(dark: true),
+          home: Scaffold(
+            body: SizedBox(
+              width: 1280,
+              height: 720,
+              child: TvBrowseRail(
+                key: const ValueKey('rail'),
+                hubs: hubs,
+                initialHubId: initialHubId,
+                iconForHub: (_, _) => Icons.tv_rounded,
+                onActiveHubChanged: (hub, _) => activeHubIds.add(hub.id),
+              ),
+            ),
+          ),
+        ),
+      );
+    }
+
+    const castHub = MediaHub(id: 'detail_actors', title: 'Cast', type: 'person', items: <MediaItem>[]);
+    const episodesHub = MediaHub(id: 'detail_episodes', title: 'Episodes', type: 'episode', items: <MediaItem>[]);
+
+    await tester.pumpWidget(buildRail(const [castHub]));
+    await tester.pump();
+
+    await tester.pumpWidget(buildRail(const [castHub], initialHubId: episodesHub.id));
+    await tester.pump();
+
+    await tester.pumpWidget(buildRail(const [episodesHub, castHub], initialHubId: episodesHub.id));
+    await tester.pump();
+
+    expect(activeHubIds, containsAllInOrder(['detail_actors', 'detail_episodes']));
+    expect(activeHubIds.last, 'detail_episodes');
+  });
+
   testWidgets('selects preferred item when active hub items are populated asynchronously', (tester) async {
     final focusedItemIds = <String>[];