refactor: 移除 LiteLLM proxy 架构，后端直连 Provider API

- 移除 backend/scripts/build_litellm_proxy_config.py
- 简化 LiteLLMService，移除 run_completion_with_cost 方法
- AgentScopeRunner 改为从 LlmFactory 获取 api_base 和 api_key
- 部署配置移除 litellm/litellm-config-job 服务
- Flutter 新增 AuthBootScreen 引导页
- Android 添加通知权限 (POST_NOTIFICATIONS, RECEIVE_BOOT_COMPLETED, SCHEDULE_EXACT_ALARM)
- 优化 LocalNotificationService 调度失败 fallback
- 更新 manifest.json (version 3)

apps/lib/core/notifications/local_notification_service.dart

@@ -76,16 +76,29 @@ class LocalNotificationService {
       ),
     );
 
-    await _plugin.zonedSchedule(
-      notificationId,
-      event.title,
-      _buildReminderBody(event, reminderMinutes),
-      scheduledAt,
-      details,
-      androidScheduleMode: AndroidScheduleMode.exactAllowWhileIdle,
-      uiLocalNotificationDateInterpretation:
-          UILocalNotificationDateInterpretation.absoluteTime,
-    );
+    try {
+      await _plugin.zonedSchedule(
+        notificationId,
+        event.title,
+        _buildReminderBody(event, reminderMinutes),
+        scheduledAt,
+        details,
+        androidScheduleMode: AndroidScheduleMode.exactAllowWhileIdle,
+        uiLocalNotificationDateInterpretation:
+            UILocalNotificationDateInterpretation.absoluteTime,
+      );
+    } catch (_) {
+      await _plugin.zonedSchedule(
+        notificationId,
+        event.title,
+        _buildReminderBody(event, reminderMinutes),
+        scheduledAt,
+        details,
+        androidScheduleMode: AndroidScheduleMode.inexactAllowWhileIdle,
+        uiLocalNotificationDateInterpretation:
+            UILocalNotificationDateInterpretation.absoluteTime,
+      );
+    }
   }
 
   Future<void> cancelEventReminder(String eventId) async {