ops(systemd): 添加 systemd 服务，自动恢复崩溃进程

- 创建 yzr-platform.service（Restart=always，崩溃后10秒恢复）
- 更新 AGENTS.md 命令文档
- 替换原来的 setsid/nohup 启动方式

AGENTS.md

@@ -11,7 +11,14 @@
 ## Commands
 
 ```bash
-# Start server (with detach to survive shell timeout)
+# Start/stop/restart server (systemd service, auto-restart on failure)
+systemctl start yzr-platform.service   # 启动
+systemctl stop yzr-platform.service    # 停止
+systemctl restart yzr-platform.service # 重启
+systemctl status yzr-platform.service  # 查看状态
+journalctl -u yzr-platform.service -n 50 --no-pager  # 查看日志
+
+# Fallback: start without systemd (用于调试)
 cd /root/openclaw-workspace/projects/yu-zhi-ran
 setsid ./start-platform.sh 8001