feat: Add natural D-pad navigation for hub sections

- Add left navigation from hubs to sidebar when at leftmost item
- Add up navigation from first hub to tab bar (Libraries) or hero section (Discover)
- Enhance HubSection with onNavigateLeft and onNavigateUp callbacks
- Update _handleVerticalNavigation to return false at top boundary for proper UP handling
- Implement _navigateToSidebar() in Library Recommended tab and Discover screen
- Update all HubSection instances with proper navigation callbacks

lib/screens/discover_screen.dart

@@ -28,6 +28,7 @@ import '../mixins/watch_state_aware.dart';
 import '../utils/watch_state_notifier.dart';
 import '../utils/app_logger.dart';
 import '../utils/provider_extensions.dart';
+import 'main_screen.dart';
 import '../utils/video_player_navigation.dart';
 import '../utils/layout_constants.dart';
 import '../utils/platform_detector.dart';
@@ -178,6 +179,12 @@ class _DiscoverScreenState extends State<DiscoverScreen>
     return false;
   }
 
+  /// Navigate to the sidebar (called when user presses left at leftmost item)
+  void _navigateToSidebar() {
+    final focusScope = MainScreenFocusScope.of(context);
+    focusScope?.focusSidebar();
+  }
+
   @override
   void initState() {
     super.initState();
@@ -1033,6 +1040,11 @@ class _DiscoverScreenState extends State<DiscoverScreen>
                         onRemoveFromContinueWatching: _refreshContinueWatching,
                         isInContinueWatching: true,
                         onVerticalNavigation: (isUp) => _handleVerticalNavigation(0, isUp),
+                        onNavigateLeft: _navigateToSidebar,
+                        onNavigateUp: () {
+                          _heroFocusNode.requestFocus();
+                          _scrollController.animateTo(0, duration: const Duration(milliseconds: 200), curve: Curves.easeOut);
+                        },
                       ),
                     ),
 
@@ -1047,6 +1059,11 @@ class _DiscoverScreenState extends State<DiscoverScreen>
                         onRefresh: updateItem,
                         // Hub index is i + 1 if continue watching exists, otherwise i
                         onVerticalNavigation: (isUp) => _handleVerticalNavigation(_onDeck.isNotEmpty ? i + 1 : i, isUp),
+                        onNavigateLeft: _navigateToSidebar,
+                        onNavigateUp: (i == 0 && _onDeck.isEmpty) ? () {
+                          _heroFocusNode.requestFocus();
+                          _scrollController.animateTo(0, duration: const Duration(milliseconds: 200), curve: Curves.easeOut);
+                        } : null,
                       ),
                     ),
 

lib/screens/libraries/tabs/library_recommended_tab.dart

@@ -7,6 +7,7 @@ import '../../../mixins/item_updatable.dart';
 import '../../../models/plex_hub.dart';
 import '../../../models/plex_metadata.dart';
 import '../../../widgets/hub_section.dart';
+import '../../main_screen.dart';
 import 'base_library_tab.dart';
 
 /// Recommended tab for library screen
@@ -115,8 +116,13 @@ class _LibraryRecommendedTabState extends BaseLibraryTabState<PlexHub, LibraryRe
     final targetIndex = isUp ? hubIndex - 1 : hubIndex + 1;
 
     // Check if target is valid
-    if (targetIndex < 0 || targetIndex >= _hubKeys.length) {
-      // At boundary, block navigation
+    if (targetIndex < 0) {
+      // At top boundary - return false to allow onNavigateUp to handle it
+      return false;
+    }
+    
+    if (targetIndex >= _hubKeys.length) {
+      // At bottom boundary, block navigation
       return true;
     }
 
@@ -130,6 +136,12 @@ class _LibraryRecommendedTabState extends BaseLibraryTabState<PlexHub, LibraryRe
     return false;
   }
 
+  /// Navigate to the sidebar (called when user presses left at leftmost item)
+  void _navigateToSidebar() {
+    final focusScope = MainScreenFocusScope.of(context);
+    focusScope?.focusSidebar();
+  }
+
   /// Focus the first item in the first hub (for tab activation)
   @override
   void focusFirstItem() {
@@ -158,6 +170,8 @@ class _LibraryRecommendedTabState extends BaseLibraryTabState<PlexHub, LibraryRe
           onRemoveFromContinueWatching: isContinueWatching ? _refreshContinueWatching : null,
           onVerticalNavigation: (isUp) => _handleVerticalNavigation(index, isUp),
           onBack: widget.onBack,
+          onNavigateLeft: _navigateToSidebar,
+          onNavigateUp: index == 0 ? widget.onBack : null,
         );
       },
     );

lib/widgets/hub_section.dart

@@ -39,6 +39,14 @@ class HubSection extends StatefulWidget {
   /// Used to navigate focus back to the tab bar.
   final VoidCallback? onBack;
 
+  /// Called when the user presses LEFT while at the leftmost item.
+  /// Used to navigate focus to the side navigation rail.
+  final VoidCallback? onNavigateLeft;
+
+  /// Called when the user presses UP while at the topmost item (first hub).
+  /// Used to navigate focus to the tab bar.
+  final VoidCallback? onNavigateUp;
+
   const HubSection({
     super.key,
     required this.hub,
@@ -49,6 +57,8 @@ class HubSection extends StatefulWidget {
     this.showServerName = false,
     this.onVerticalNavigation,
     this.onBack,
+    this.onNavigateLeft,
+    this.onNavigateUp,
   });
 
   @override
@@ -172,6 +182,9 @@ class HubSectionState extends State<HubSection> {
         HubFocusMemory.setForHub(widget.hub.hubKey, _focusedIndex);
         _scrollToIndex(_focusedIndex);
         setState(() {});
+      } else if (widget.onNavigateLeft != null) {
+        // At leftmost item - navigate to sidebar
+        widget.onNavigateLeft!();
       }
       return KeyEventResult.handled;
     }
@@ -189,7 +202,11 @@ class HubSectionState extends State<HubSection> {
 
     // Up/Down: delegate to parent for vertical hub navigation, ALWAYS consume
     if (key.isUpKey) {
-      widget.onVerticalNavigation?.call(true);
+      final handled = widget.onVerticalNavigation?.call(true) ?? false;
+      // If not handled (at top boundary) and we have onNavigateUp, call it
+      if (!handled && widget.onNavigateUp != null) {
+        widget.onNavigateUp!();
+      }
       return KeyEventResult.handled;
     }
     if (key.isDownKey) {