fix(mobile): move update check to HomeShellPage with valid context

- Move checkForAppUpdate from SplashPage to HomeShellPage
- Use WidgetsBindingObserver to check on app resume
- Add 24-hour interval check to avoid frequent API calls
- Fix: context.go() invalidates context, so check was never executed

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/mobile-app/lib/features/auth/presentation/pages/splash_page.dart

@@ -69,8 +69,8 @@ class _SplashPageState extends ConsumerState<SplashPage> {
       context.go(RoutePaths.onboarding);
     }
 
-    // 总是检查应用更新（跳转后执行，避免阻塞启动）
-    checkForAppUpdate(context);
+    // 注意：更新检查已移至 HomeShellPage，在主页面加载后执行
+    // 这里不再调用 checkForAppUpdate，因为 context.go() 后 context 已失效
   }
 
   @override

frontend/mobile-app/lib/features/home/presentation/pages/home_shell_page.dart

@@ -4,13 +4,61 @@ import 'package:go_router/go_router.dart';
 import '../../../../core/theme/app_colors.dart';
 import '../../../../core/theme/app_dimensions.dart';
 import '../../../../routes/route_paths.dart';
+import '../../../../bootstrap.dart';
 import '../widgets/bottom_nav_bar.dart';
 
-class HomeShellPage extends ConsumerWidget {
+class HomeShellPage extends ConsumerStatefulWidget {
   final Widget child;
 
   const HomeShellPage({super.key, required this.child});
 
+  @override
+  ConsumerState<HomeShellPage> createState() => _HomeShellPageState();
+}
+
+class _HomeShellPageState extends ConsumerState<HomeShellPage>
+    with WidgetsBindingObserver {
+  /// 上次检查更新的时间
+  static DateTime? _lastCheckTime;
+
+  /// 检查间隔（24小时）
+  static const _checkInterval = Duration(hours: 24);
+
+  @override
+  void initState() {
+    super.initState();
+    WidgetsBinding.instance.addObserver(this);
+    // 首次进入时检查更新
+    WidgetsBinding.instance.addPostFrameCallback((_) {
+      _checkForUpdateIfNeeded();
+    });
+  }
+
+  @override
+  void dispose() {
+    WidgetsBinding.instance.removeObserver(this);
+    super.dispose();
+  }
+
+  @override
+  void didChangeAppLifecycleState(AppLifecycleState state) {
+    // 从后台恢复时检查更新
+    if (state == AppLifecycleState.resumed) {
+      _checkForUpdateIfNeeded();
+    }
+  }
+
+  Future<void> _checkForUpdateIfNeeded() async {
+    final now = DateTime.now();
+
+    // 如果从未检查过，或者距上次检查超过24小时，则检查
+    if (_lastCheckTime == null ||
+        now.difference(_lastCheckTime!) > _checkInterval) {
+      _lastCheckTime = now;
+      await checkForAppUpdate(context);
+    }
+  }
+
   int _getCurrentIndex(BuildContext context) {
     final location = GoRouterState.of(context).uri.path;
     if (location.startsWith(RoutePaths.ranking)) return 0;
@@ -38,9 +86,9 @@ class HomeShellPage extends ConsumerWidget {
   }
 
   @override
-  Widget build(BuildContext context, WidgetRef ref) {
+  Widget build(BuildContext context) {
     return Scaffold(
-      body: child,
+      body: widget.child,
       bottomNavigationBar: BottomNavBar(
         currentIndex: _getCurrentIndex(context),
         onTap: (index) => _onTabTapped(context, index),