refactor: 完成存储层迁移，替换AppKVStore为KvStorage

主要变更:
1. 重构存储层导入路径，将app_kv_store替换为kv_storage
2. 移除AppKVStore初始化代码，统一使用KvStorage
3. 修复壁纸健康检测逻辑，使用最新检查时间判断检测间隔
4. 调整主页头部容器高度与裁剪行为
5. 新增引导页下次显示开关与Riverpod提供者
6. 修复API响应List类型转换崩溃问题
7. 优化部分文件头注释格式

lib/main.dart

@@ -19,13 +19,11 @@ import 'core/services/network/deep_link_service.dart';
 import 'core/services/notification/local_notification_service.dart';
 import 'core/services/device/screen_wake_service.dart';
 import 'core/services/readlater/sharing_receiver_service.dart';
-import 'core/services/sound_service.dart';
 import 'core/services/device/battery_optimization_service.dart';
 import 'core/services/performance/performance_orchestrator.dart';
 import 'core/services/notification/readlater_reminder_service.dart';
 import 'core/services/data/home_widget_service.dart';
 import 'core/services/clipboard_monitor_service.dart';
-import 'core/storage/app_kv_store.dart';
 import 'core/storage/kv_storage.dart';
 import 'core/utils/logger.dart';
 import 'core/utils/platform/platform_utils.dart' as pu;
@@ -85,13 +83,6 @@ void main() async {
         Log.e('KV 存储初始化失败', e, st);
       }
 
-      try {
-        await AppKVStore.init();
-        if (pu.isOhos) Log.i('🟢 [OHOS] AppKVStore 初始化完成');
-      } catch (e, st) {
-        Log.e('AppKVStore 初始化失败', e, st);
-      }
-
       try {
         await WallpaperFavoriteService.init();
         Log.i('壁纸收藏服务初始化完成');
@@ -168,7 +159,7 @@ void main() async {
       }
 
       try {
-        await SoundService.init();
+        // SoundService 初始化已由 SoundNotifier.build() 自动完成
         if (pu.isOhos) Log.i('🟢 [OHOS] 音效服务初始化完成');
       } catch (e, st) {
         Log.e('音效服务初始化失败', e, st);