- Implement Workerman-based `xboard:ws-server` for real-time node synchronization.
- Support custom routes, outbounds, and certificate configurations via JSON.
- Optimize scheduled tasks with `lazyById` to minimize memory footprint.
- Enhance reactivity using Observers for `Plan`, `Server`, and `ServerRoute`.
- Expand protocol support for `httpupgrade`, `h2`, and `mieru`.
- Dockerfile: backup plugins/ to /opt/default-plugins/ at build time
- Replace exec/git-based restore with pure PHP File::copyDirectory()
- Only restore plugins defined in Plugin::PROTECTED_PLUGINS
- Delete target directory before copy to prevent stale files
- Remove function_exists('exec') guard (no longer needed)
