dsh-file-browser: Add a full-disk file browser bar to the DSH chat interface

dsh-file-browser is a DSH client plugin developed by Clearchenpro (MIT licensed), designed to provide native file browsing access for Web-based DSH sessions. The plugin adds a file browsing sidebar to the right side of the chat interface, supporting hierarchical browsing of the host disk directories, offering sorting by name, size, and modification time, and providing breadcrumb navigation. Users can drag and drop images (e.g., PNG, JPG) as attachments to insert them into the chat, or write other file paths in the draft using backtick format. Additionally, it supports inline operations such as sending paths directly, copying paths, or opening them with the system default application. The plugin uses server-side streaming scanning and limits records to 1000 per layer by default. It also supports Chinese/English bilingual interfaces. Installation requires registering the plugin via the `dsh plugin add` command and restarting the instance. Please note that this plugin is only applicable to Windows.