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/lib/features/calendar/ui/widgets/create_event_sheet.dart

@@ -57,6 +57,17 @@ class CreateEventSheet extends StatefulWidget {
 
 class _CreateEventSheetState extends State<CreateEventSheet>
     with SingleTickerProviderStateMixin {
+  static const List<int?> _defaultReminderOptions = [
+    null,
+    0,
+    5,
+    10,
+    15,
+    30,
+    60,
+    120,
+  ];
+
   late TabController _tabController;
   final _titleController = TextEditingController();
   final _descriptionController = TextEditingController();
@@ -89,7 +100,9 @@ class _CreateEventSheetState extends State<CreateEventSheet>
       _endDate = event.endAt;
       _endTime = event.endAt;
       _selectedColor = event.metadata?.color ?? '#3B82F6';
-      _reminderMinutes = event.metadata?.reminderMinutes ?? 15;
+      _reminderMinutes = _sanitizeReminderMinutes(
+        event.metadata?.reminderMinutes,
+      );
     } else {
       final now =
           widget.initialDate ?? _roundToNearestMinute(DateTime.now(), 5);
@@ -512,7 +525,7 @@ class _CreateEventSheetState extends State<CreateEventSheet>
   }
 
   Widget _buildReminderPicker() {
-    const options = <int?>[null, 0, 5, 10, 15, 30, 60, 120];
+    final options = _buildReminderOptions();
     String labelOf(int? value) {
       if (value == null) {
         return '无提醒';
@@ -573,6 +586,24 @@ class _CreateEventSheetState extends State<CreateEventSheet>
     );
   }
 
+  int? _sanitizeReminderMinutes(int? minutes) {
+    if (minutes == null || minutes < 0) {
+      return null;
+    }
+    return minutes;
+  }
+
+  List<int?> _buildReminderOptions() {
+    final current = _sanitizeReminderMinutes(_reminderMinutes);
+    final nonNull = _defaultReminderOptions.whereType<int>().toSet();
+    if (current != null) {
+      nonNull.add(current);
+    }
+
+    final sorted = nonNull.toList()..sort();
+    return [null, ...sorted];
+  }
+
   Future<void> _saveEvent() async {
     if (_titleController.text.trim().isEmpty || _saving) return;
     setState(() {