refactor(storage): 迁移 AsyncStorage 至 expo-sqlite/kv-store

- 统一替换所有 @react-native-async-storage/async-storage 导入为自定义 kvStore
- 新增 kvStore.ts 封装 expo-sqlite/kv-store，保持与 AsyncStorage 完全兼容
- 新增同步读写方法，提升性能
- 引入 expo-sqlite 依赖并更新 lock 文件

BREAKING CHANGE: 移除 @react-native-async-storage/async-storage 依赖，需重新安装依赖并清理旧数据

services/backgroundTaskManager.ts

@@ -1,7 +1,7 @@
 import { store } from '@/store';
 import { log } from '@/utils/logger';
 import { StandReminderHelpers, WaterNotificationHelpers } from '@/utils/notificationHelpers';
-import AsyncStorage from '@react-native-async-storage/async-storage';
+import AsyncStorage from '@/utils/kvStore';
 import * as BackgroundTask from 'expo-background-task';
 import * as TaskManager from 'expo-task-manager';
 import { TaskManagerTaskBody } from 'expo-task-manager';