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

store/exerciseLibrarySlice.ts

@@ -5,7 +5,7 @@ import {
   type ExerciseConfigResponse,
   type ExerciseLibraryItem,
 } from '@/services/exercises';
-import AsyncStorage from '@react-native-async-storage/async-storage';
+import AsyncStorage from '@/utils/kvStore';
 import { createAsyncThunk, createSlice, PayloadAction } from '@reduxjs/toolkit';
 
 export interface ExerciseLibraryState {