refactor(library): drop unread QueueTab page parameters and fast-scroller callbacks

Nothing read parentPageController, parentPageIndex or nextPageIndex, and the
Library tab root watched showExtensionStore only to compute them, so toggling
that setting rebuilt the tab for nothing. No caller passed the fast scroller
onDragStart/onDragEnd callbacks.

lib/screens/main_shell.dart

@@ -819,10 +819,7 @@ class _MainShellState extends ConsumerState<MainShell>
         navigatorKey: _libraryTabNavigatorKey,
         observers: [_libraryPreviewStopObserver],
         heroAnimationsEnabled: heroAnimationsEnabled,
-        child: _LibraryTabRoot(
-          parentPageController: _pageController,
-          isTabActive: _currentIndex == 1,
-        ),
+        child: _LibraryTabRoot(isTabActive: _currentIndex == 1),
       ),
       if (showStore)
         _TabNavigator(
@@ -1224,25 +1221,13 @@ class _PreviewStopNavigatorObserver extends NavigatorObserver {
 }
 
 class _LibraryTabRoot extends ConsumerWidget {
-  final PageController parentPageController;
   final bool isTabActive;
 
-  const _LibraryTabRoot({
-    required this.parentPageController,
-    required this.isTabActive,
-  });
+  const _LibraryTabRoot({required this.isTabActive});
 
   @override
   Widget build(BuildContext context, WidgetRef ref) {
-    final showStore = ref.watch(
-      settingsProvider.select((s) => s.showExtensionStore),
-    );
-    return QueueTab(
-      isTabActive: isTabActive,
-      parentPageController: parentPageController,
-      parentPageIndex: 1,
-      nextPageIndex: showStore ? 2 : 3,
-    );
+    return QueueTab(isTabActive: isTabActive);
   }
 }
 

lib/screens/queue_tab.dart

@@ -239,18 +239,8 @@ DownloadHistoryItem? _historyItemForCompletionBridge(
 class QueueTab extends ConsumerStatefulWidget {
   final String? librarySection;
   final bool isTabActive;
-  final PageController? parentPageController;
-  final int parentPageIndex;
-  final int? nextPageIndex;
 
-  const QueueTab({
-    super.key,
-    this.librarySection,
-    this.isTabActive = true,
-    this.parentPageController,
-    this.parentPageIndex = 1,
-    this.nextPageIndex,
-  });
+  const QueueTab({super.key, this.librarySection, this.isTabActive = true});
 
   @override
   ConsumerState<QueueTab> createState() => _QueueTabState();

lib/widgets/library_fast_scroller.dart

@@ -19,8 +19,6 @@ class LibraryFastScroller extends StatefulWidget {
     super.key,
     required this.child,
     required this.labelAt,
-    this.onDragStart,
-    this.onDragEnd,
     this.topPadding = 0,
     this.bottomPadding = 0,
   });
@@ -32,9 +30,6 @@ class LibraryFastScroller extends StatefulWidget {
   /// Label for the row at [fraction] of the scrollable content, or null.
   final String? Function(double fraction) labelAt;
 
-  final VoidCallback? onDragStart;
-  final VoidCallback? onDragEnd;
-
   /// Height of the pinned header. While an outer scroll view is expanded,
   /// only its overlap with this viewport is reserved.
   final double topPadding;
@@ -86,10 +81,6 @@ class _LibraryFastScrollerState extends State<LibraryFastScroller> {
     _hideTimer?.cancel();
     _position?.removeListener(_onPositionChanged);
     _outerPosition?.removeListener(_onOuterPositionChanged);
-    if (_dragging) {
-      final onDragEnd = widget.onDragEnd;
-      WidgetsBinding.instance.addPostFrameCallback((_) => onDragEnd?.call());
-    }
     super.dispose();
   }
 
@@ -155,7 +146,6 @@ class _LibraryFastScrollerState extends State<LibraryFastScroller> {
       _dragging = true;
       _show();
     });
-    widget.onDragStart?.call();
   }
 
   void _updateDrag(DragUpdateDetails details, double trackHeight) {
@@ -197,7 +187,6 @@ class _LibraryFastScrollerState extends State<LibraryFastScroller> {
       _dragging = false;
       _show();
     });
-    widget.onDragEnd?.call();
   }
 
   @override