fix: 完善低权限备份恢复与只读部署密钥支持

ops/README.md

@@ -14,7 +14,7 @@
 - 程序：`/opt/grain-auto-deploy/auto_deploy.py`
 - 配置：`/etc/grain-auto-deploy.json`
 - 版本及文件清单：`/var/lib/grain-auto-deploy/backend.json`、`frontend.json`
-- 备份：`/www/backup/grain-auto-deploy/`
+- 备份：`/var/lib/grain-auto-deploy/backups/`
 - 日志：`/var/log/grain-auto-deploy.log`，以及 `journalctl -u grain-auto-deploy.service`
 
 运维命令：