feat: 添加 App 检查更新功能

- 前端：设置页面添加检查更新菜单项，从 pubspec.yaml 动态获取版本号
- 后端：新增 /api/v1/app/check-updates 接口，自动扫描 releases 目录对比版本
- 配置：新增 AppVersionSettings，支持通过环境变量配置版本和下载链接
- Docker：添加 releases 目录挂载

apps/lib/main.dart

@@ -3,6 +3,7 @@ import 'dart:async';
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 
+import 'core/constants/app_constants.dart';
 import 'core/di/injection.dart';
 import 'core/notifications/local_notification_service.dart';
 import 'core/router/app_router.dart';
@@ -16,6 +17,7 @@ import 'features/calendar/data/services/calendar_service.dart';
 void main() async {
   WidgetsFlutterBinding.ensureInitialized();
   await configureDependencies();
+  await AppConstants.init();
 
   final authBloc = sl<AuthBloc>();
   authBloc.add(AuthStarted());