feat: 实现 Auth 全局状态机与 401 统一处理机制

- 新增 AuthSessionInvalidated 事件处理 token 失效场景
- ApiInterceptor 新增 authFailureCallback 单飞机制
- AuthBloc 区分 manual logout 与 auto expiry 语义
- 新增 startup recovery fallback 防止启动卡死

feat: 重构 Calendar DayWeek 视图事件布局引擎

- 新增 DayEventLayoutEngine 解耦事件计算与渲染
- 新增 DayTimelineMetrics 统一时间轴常量
- 新增 DayViewScale 支持捏合缩放

feat: 新增 Settings 页面共享 UI 组件

- 新增 BackTitlePageHeader 统一页面 header
- 新增 DetailHeaderActionMenu 统一操作菜单
- 新增 DestructiveActionSheet 统一删除确认
- 新增 AppToggleSwitch 统一开关组件

feat: Chat UI Schema 支持导航操作

- 支持 navigation 类型 action 触发内部路由跳转
- 新增路径验证与参数处理

chore: 更新相关测试覆盖 auth 失效路径

apps/test/core/api/api_interceptor_test.dart

@@ -36,8 +36,13 @@ void main() {
     when(() => tokenStorage.getAccessToken()).thenAnswer((_) async => null);
   });
 
-  DioException _unauthorized(String path) {
-    final requestOptions = RequestOptions(path: path);
+  DioException _unauthorized(String path, {bool withAuthHeader = false}) {
+    final requestOptions = RequestOptions(
+      path: path,
+      headers: withAuthHeader
+          ? <String, dynamic>{'Authorization': 'Bearer expired'}
+          : null,
+    );
     return DioException(
       requestOptions: requestOptions,
       response: Response<dynamic>(
@@ -109,4 +114,30 @@ void main() {
 
     expect(refreshCalls, 1);
   });
+
+  test('并发401刷新失败仅触发一次auth failure回调', () async {
+    var refreshCalls = 0;
+    var authFailureCalls = 0;
+    interceptor.onTokenRefresh = () async {
+      refreshCalls += 1;
+      await Future<void>.delayed(const Duration(milliseconds: 20));
+      return false;
+    };
+    interceptor.onAuthFailure = () async {
+      authFailureCalls += 1;
+    };
+
+    interceptor.onError(
+      _unauthorized('/api/v1/agent/history', withAuthHeader: true),
+      handler,
+    );
+    interceptor.onError(
+      _unauthorized('/api/v1/agent/history', withAuthHeader: true),
+      handler,
+    );
+    await Future<void>.delayed(const Duration(milliseconds: 80));
+
+    expect(refreshCalls, 1);
+    expect(authFailureCalls, 1);
+  });
 }