主要合入内容：

- 文件管理器分页加载、排序偏好、桌面表头排序、移动端排序菜单、Ctrl/Cmd+F搜索、Esc 关闭搜索、鼠标右滑返回上级。
- 移动端同步状态页、同步统计卡片、同步任务/累计统计事件、同步页布局更新。
- Android 相册同步默认路径改为 DCIM/Camera，下载路径改用 external_path。
- Rust sync-core 更新：Android 日志依赖、AlbumUpload/AlbumDownload、MirrorWcf 统计修复、Linux FUSE镜像挂载与读写同步支持。

- 依赖更新：external_path、fl_chart、pdfrx 升级，并修了 pdfrx 新版本的deprecated API。
- 新增文件包括：sort_options.dart、sync_page_android.dart、sync_stats_card.dart、platform/fuse.rs、sync_engine/fuse.rs。

lib/presentation/pages/shell/app_shell.dart

@@ -1,9 +1,11 @@
+import 'package:cloudreve4_flutter/presentation/providers/admin_provider.dart';
 import 'package:cloudreve4_flutter/presentation/providers/auth_provider.dart';
 import 'package:cloudreve4_flutter/presentation/providers/download_manager_provider.dart';
 import 'package:cloudreve4_flutter/presentation/providers/file_manager_provider.dart';
 import 'package:cloudreve4_flutter/presentation/providers/navigation_provider.dart';
 import 'package:cloudreve4_flutter/presentation/providers/sync_provider.dart';
 import 'package:cloudreve4_flutter/presentation/providers/upload_manager_provider.dart';
+import 'package:cloudreve4_flutter/presentation/providers/user_setting_provider.dart';
 import 'package:cloudreve4_flutter/presentation/widgets/announcement_dialog.dart';
 import 'package:cloudreve4_flutter/presentation/widgets/gesture_handler_mixin.dart';
 import 'package:cloudreve4_flutter/presentation/widgets/glassmorphism_container.dart';
@@ -57,12 +59,18 @@ class _AppShellState extends State<AppShell>
   final Set<int> _visitedPageIndexes = <int>{0};
   late AnimationController _syncSpinController;
   String? _lastClipboardShareId;
+  String? _lastUserId;
+  bool _cachedShowSyncTab = false;
 
-  bool get _showSyncTab =>
-      defaultTargetPlatform != TargetPlatform.android &&
-      defaultTargetPlatform != TargetPlatform.iOS;
+  static bool _shouldShowSyncTab(double screenWidth) {
+    if (defaultTargetPlatform != TargetPlatform.android &&
+        defaultTargetPlatform != TargetPlatform.iOS) {
+      return true;
+    }
+    return screenWidth >= 800;
+  }
 
-  List<Widget> get _pages => _showSyncTab
+  List<Widget> _pages(bool showSyncTab) => showSyncTab
       ? [
           const OverviewPage(),
           const FilesPage(),
@@ -78,7 +86,7 @@ class _AppShellState extends State<AppShell>
         ];
 
   int _clampedIndex(int index) {
-    final maxIndex = _pages.length - 1;
+    final maxIndex = _pages(_cachedShowSyncTab).length - 1;
     if (index < 0) return 0;
     if (index > maxIndex) return maxIndex;
     return index;
@@ -95,6 +103,7 @@ class _AppShellState extends State<AppShell>
     WidgetsBinding.instance.addPostFrameCallback((_) {
       _showPostLoginAnnouncement();
       _checkClipboardShareLink();
+      _lastUserId = context.read<AuthProvider>().user?.id;
     });
   }
 
@@ -112,6 +121,56 @@ class _AppShellState extends State<AppShell>
     }
   }
 
+  void _handleTabSelected(int index) {
+    final nav = Provider.of<NavigationProvider>(context, listen: false);
+    nav.setIndex(index);
+
+    final userSetting = Provider.of<UserSettingProvider>(
+      context,
+      listen: false,
+    );
+    if (index == 0 || index == _pages(_cachedShowSyncTab).length - 1) {
+      userSetting.loadCapacity();
+    }
+  }
+
+  void _checkUserChange(AuthProvider auth) {
+    final currentUserId = auth.user?.id;
+    if (_lastUserId != null && currentUserId != _lastUserId) {
+      _lastUserId = currentUserId;
+      Future.microtask(() {
+        if (mounted) _resetProvidersOnUserChange();
+      });
+    } else if (_lastUserId == null && currentUserId != null) {
+      _lastUserId = currentUserId;
+    }
+  }
+
+  void _resetProvidersOnUserChange() {
+    final fileManager = Provider.of<FileManagerProvider>(
+      context,
+      listen: false,
+    );
+    final userSetting = Provider.of<UserSettingProvider>(
+      context,
+      listen: false,
+    );
+    final admin = Provider.of<AdminProvider>(context, listen: false);
+    final sync = Provider.of<SyncProvider>(context, listen: false);
+
+    fileManager.clearFiles();
+    userSetting.clear();
+    admin.clear();
+
+    if (sync.engineInitialized) {
+      sync.resetSync();
+    }
+
+    final nav = Provider.of<NavigationProvider>(context, listen: false);
+    nav.setIndex(0);
+    userSetting.loadCapacity();
+  }
+
   Future<void> _showPostLoginAnnouncement() async {
     final authProvider = context.read<AuthProvider>();
     if (!authProvider.isAuthenticated) return;
@@ -193,6 +252,7 @@ class _AppShellState extends State<AppShell>
   Widget build(BuildContext context) {
     final screenWidth = MediaQuery.of(context).size.width;
     final isDesktop = screenWidth >= 1000;
+    _cachedShowSyncTab = _shouldShowSyncTab(screenWidth);
 
     return PopScope(
       canPop: false,
@@ -217,8 +277,9 @@ class _AppShellState extends State<AppShell>
           }
         }
       },
-      child: Consumer<NavigationProvider>(
-        builder: (context, navProvider, _) {
+      child: Consumer2<AuthProvider, NavigationProvider>(
+        builder: (context, auth, navProvider, _) {
+          _checkUserChange(auth);
           if (isDesktop) {
             return _buildDesktopLayout(context, navProvider);
           }
@@ -229,7 +290,7 @@ class _AppShellState extends State<AppShell>
   }
 
   Widget _buildPageContent(BuildContext context, int currentIndex) {
-    final pages = _pages;
+    final pages = _pages(_cachedShowSyncTab);
     final visibleIndex = _clampedIndex(currentIndex);
     _visitedPageIndexes.add(visibleIndex);
 
@@ -297,7 +358,7 @@ class _AppShellState extends State<AppShell>
             return NavigationBar(
               height: 64,
               selectedIndex: _clampedIndex(navProvider.currentIndex),
-              onDestinationSelected: (i) => navProvider.setIndex(i),
+              onDestinationSelected: _handleTabSelected,
               destinations: [
                 const NavigationDestination(
                   icon: Icon(LucideIcons.layoutDashboard),
@@ -322,7 +383,7 @@ class _AppShellState extends State<AppShell>
                   ),
                   label: '任务',
                 ),
-                if (_showSyncTab)
+                if (_cachedShowSyncTab)
                   NavigationDestination(
                     icon: Consumer<SyncProvider>(
                       builder: (context, sync, _) {
@@ -373,15 +434,18 @@ class _AppShellState extends State<AppShell>
         children: [
           NavigationRail(
             selectedIndex: _clampedIndex(navProvider.currentIndex),
-            onDestinationSelected: (i) => navProvider.setIndex(i),
+            onDestinationSelected: _handleTabSelected,
             leading: Padding(
               padding: const EdgeInsets.symmetric(vertical: 16),
               child: GestureDetector(
-                onTap: () => navProvider.setIndex(_pages.length - 1),
+                onTap: () =>
+                    navProvider.setIndex(_pages(_cachedShowSyncTab).length - 1),
                 child: Container(
                   decoration: BoxDecoration(
                     shape: BoxShape.circle,
-                    border: navProvider.currentIndex == _pages.length - 1
+                    border:
+                        navProvider.currentIndex ==
+                            _pages(_cachedShowSyncTab).length - 1
                         ? Border.all(
                             color: theme.colorScheme.primary,
                             width: 2.5,
@@ -424,7 +488,7 @@ class _AppShellState extends State<AppShell>
                 selectedIcon: const Icon(LucideIcons.listChecks, weight: 700),
                 label: const Text('任务'),
               ),
-              if (_showSyncTab)
+              if (_cachedShowSyncTab)
                 NavigationRailDestination(
                   icon: Consumer<SyncProvider>(
                     builder: (context, sync, _) {