fix(wechat): 修正小程序access token刷新频率

- 将定时任务表达式从每2小时任意分钟调整为每2小时整点执行
- 确保access token在有效期内被及时刷新
- 避免因频繁请求导致的token失效问题

src/Cron/AccessTokenCron.php

@@ -30,7 +30,7 @@ class AccessTokenCron extends BaseJob
         $this->cacheKey = Cache::getCachekey($this->accessToken->getKey());
     }
 
-    #[Cron('* * */2 * * *', 'wechat.refreshMiniAppAccessToken')]
+    #[Cron('0 0 */2 * * *', 'wechat.refreshMiniAppAccessToken')]
     public function refreshMiniAppAccessToken(): void
     {
         $expireIn = $this->execute();