dsh-workspace-dock: Sidebar Workspace Dock Bar

The DeepSeek Harness plugin `dsh-workspace-dock` is specifically designed to address the clutter in the sidebar of the web interface. It provides a visual Dock bar on the left side of the sidebar, supporting workspace filtering, menu management (renaming, archiving, etc.), and custom icons. The plugin features narrow/wide bar switching, status badge display, and a home entry function, and is fully implemented with a plugin-based architecture without modifying core files, compatible with dsh 0.1.0-rc.6.