Fix WebUI backup path: use /home/appuser/.hermes-web-ui/

The app stores its SQLite DB (accounts, channel configs, WeChat
credentials) in ~/.hermes-web-ui/ (= /home/appuser/.hermes-web-ui/),
not /data/.hermes-web-ui/ which only holds the legacy .token file.

src/data_sync.py

@@ -57,7 +57,7 @@ class DatasetManager:
             'state_db': {'path': self.hermes_home / 'state.db', 'skip_backup': False},
             'logs': {'path': self.hermes_home / 'logs', 'skip_backup': True},  # 日志大且不重要
             'cron': {'path': self.hermes_home / 'cron', 'skip_backup': False},
-            'webui_dir': {'path': Path('/data/.hermes-web-ui'), 'skip_backup': False},
+            'webui_dir': {'path': Path('/home/appuser/.hermes-web-ui'), 'skip_backup': False},
             'image_cache': {'path': self.hermes_home / 'image_cache', 'skip_backup': True},  # 图片缓存大
             'baoyu_skills': {'path': Path('/home/appuser/.baoyu-skills'), 'skip_backup': False},
             'weixin': {'path': self.hermes_home / 'weixin', 'skip_backup': False},