refactor(core): consolidate shared app foundations

lib/screens/libraries/tabs/library_collections_tab.dart

@@ -81,38 +81,34 @@ class _LibraryCollectionsTabState extends BaseLibraryTabState<MediaItem, Library
 
   @override
   Future<void> loadItems() async {
-    setState(() {
-      isLoading = true;
-      errorMessage = null;
-      items = [];
-      resetPaginationState();
-    });
-
-    try {
-      final initialPage = await loadInitialPageWithStatus(_pageSize);
-      if (!initialPage.applied || !mounted) return;
-
-      setState(() {
-        items = loadedItems.values.toList();
+    await loadInitialPaginatedItems(
+      pageSize: _pageSize,
+      resetViewState: () {
+        isLoading = true;
+        errorMessage = null;
+        items = [];
+      },
+      applyLoadedItems: (loaded) {
+        items = loaded;
         isLoading = false;
-      });
-
-      hasLoadedData = true;
-      tryFocus();
-
-      if (widget.onDataLoaded != null) {
-        WidgetsBinding.instance.addPostFrameCallback((_) {
-          if (mounted) widget.onDataLoaded!();
-        });
-      }
-    } catch (e, st) {
-      appLogger.e('Error loading $errorContext', error: e, stackTrace: st);
-      if (!mounted) return;
-      setState(() {
-        errorMessage = 'Failed to load $errorContext: ${e.toString()}';
+      },
+      applyError: (error, _) {
+        errorMessage = 'Failed to load $errorContext: ${error.toString()}';
         isLoading = false;
-      });
-    }
+      },
+      onLoaded: (_, _) {
+        hasLoadedData = true;
+        tryFocus();
+        if (widget.onDataLoaded != null) {
+          WidgetsBinding.instance.addPostFrameCallback((_) {
+            if (mounted) widget.onDataLoaded!();
+          });
+        }
+      },
+      onError: (error, stackTrace) {
+        appLogger.e('Error loading $errorContext', error: error, stackTrace: stackTrace);
+      },
+    );
   }
 
   @override

lib/screens/libraries/tabs/library_playlists_tab.dart

@@ -86,38 +86,34 @@ class _LibraryPlaylistsTabState extends BaseLibraryTabState<MediaPlaylist, Libra
 
   @override
   Future<void> loadItems() async {
-    setState(() {
-      isLoading = true;
-      errorMessage = null;
-      items = [];
-      resetPaginationState();
-    });
-
-    try {
-      final initialPage = await loadInitialPageWithStatus(_pageSize);
-      if (!initialPage.applied || !mounted) return;
-
-      setState(() {
-        items = loadedItems.values.toList();
+    await loadInitialPaginatedItems(
+      pageSize: _pageSize,
+      resetViewState: () {
+        isLoading = true;
+        errorMessage = null;
+        items = [];
+      },
+      applyLoadedItems: (loaded) {
+        items = loaded;
         isLoading = false;
-      });
-
-      hasLoadedData = true;
-      tryFocus();
-
-      if (widget.onDataLoaded != null) {
-        WidgetsBinding.instance.addPostFrameCallback((_) {
-          if (mounted) widget.onDataLoaded!();
-        });
-      }
-    } catch (e, st) {
-      appLogger.e('Error loading $errorContext', error: e, stackTrace: st);
-      if (!mounted) return;
-      setState(() {
-        errorMessage = 'Failed to load $errorContext: ${e.toString()}';
+      },
+      applyError: (error, _) {
+        errorMessage = 'Failed to load $errorContext: ${error.toString()}';
         isLoading = false;
-      });
-    }
+      },
+      onLoaded: (_, _) {
+        hasLoadedData = true;
+        tryFocus();
+        if (widget.onDataLoaded != null) {
+          WidgetsBinding.instance.addPostFrameCallback((_) {
+            if (mounted) widget.onDataLoaded!();
+          });
+        }
+      },
+      onError: (error, stackTrace) {
+        appLogger.e('Error loading $errorContext', error: error, stackTrace: stackTrace);
+      },
+    );
   }
 
   @override

lib/screens/libraries/tabs/library_recommended_tab.dart

@@ -4,6 +4,7 @@ import '../../../media/ids.dart';
 import 'package:flutter/material.dart';
 import 'package:material_symbols_icons/symbols.dart';
 
+import '../../../focus/hub_vertical_navigation.dart';
 import '../../../i18n/strings.g.dart';
 import '../../../media/media_hub.dart';
 import '../../../media/media_item.dart';
@@ -267,27 +268,15 @@ class _LibraryRecommendedTabState extends BaseLibraryTabState<MediaHub, LibraryR
 
   /// Handle vertical navigation between hubs
   bool _handleVerticalNavigation(int hubIndex, bool isUp) {
-    final targetIndex = isUp ? hubIndex - 1 : hubIndex + 1;
-
-    // Check if target is valid
-    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;
-    }
-
-    // Navigate to target hub with column memory
-    final targetState = _hubKeys[targetIndex].currentState;
-    if (targetState != null) {
-      targetState.requestFocusFromMemory();
-      return true;
-    }
-
-    return false;
+    return navigateVerticalHubRows(
+      hubCount: items.length,
+      hubIndex: hubIndex,
+      isUp: isUp,
+      propagateTopBoundary: true,
+      requestFocus: (targetIndex) {
+        _hubKeys[targetIndex].currentState?.requestFocusFromMemory();
+      },
+    );
   }
 
   /// Focus the first item in the first hub (for tab activation)