dsh-compact-button: One-Click Context Compression and New Session Creation

`dsh-compact-button` is a DSH Web client plugin maintained by `shyuan-hub`, designed to eliminate the hassle of manually compressing long conversations. It adds “Compress Context” and “New Session” buttons to the context meter panel, supports one-click submission of the `/compact` command with real-time status feedback, and follows the system language to switch between English and Chinese. The plugin is non-invasive; it must be installed via command and take effect after a restart, making it suitable for developers who frequently manage context windows.