chore: change backup interval from 30 minutes to 3 hours

Dockerfile

@@ -144,8 +144,8 @@ cat > /root/.openclaw/openclaw.json <<EOF\n\
 }\n\
 EOF\n\
 \n\
-# 启动定时备份进程 (每 30 分钟执行一次，增强安全性)\n\
-(while true; do sleep 1800; python3 /usr/local/bin/sync.py backup; done) &\n\
+# 启动定时备份进程 (每 3 小时执行一次，增强安全性)\n\
+(while true; do sleep 10800; python3 /usr/local/bin/sync.py backup; done) &\n\
 \n\
 # 启动 OpenClaw 网关\n\
 openclaw doctor --fix\n\