feat(sync): 云同步专用端口 apic.openless.top:9443、按钮间距与云同步服务端交接文档 - #1053

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/