fix: token过期自动跳转登录页

- dio_client.dart: 401错误时触发onUnauthorized回调
- main.dart: 连接回调到AuthProvider.forceLogout
- 完整链路: 401 -> 清除token -> 强制登出 -> 显示LoginPage

flutter_monisuo/lib/main.dart

@@ -94,7 +94,12 @@ class MyApp extends StatelessWidget {
       Provider<BonusService>(create: (_) => BonusService(dioClient)),
       // State Management
       ChangeNotifierProvider<AuthProvider>(
-        create: (ctx) => AuthProvider(ctx.read<UserService>()),
+        create: (ctx) {
+          final authProvider = AuthProvider(ctx.read<UserService>());
+          // token 过期时，DioClient 回调 AuthProvider 强制登出
+          dioClient.onUnauthorized = authProvider.forceLogout;
+          return authProvider;
+        },
       ),
       ChangeNotifierProvider<MarketProvider>(
         create: (ctx) => MarketProvider(ctx.read<MarketService>()),