dsh-open-explorer: Add entry to open Workspace folder in DSH Web GUI

dsh-open-explorer is a community plugin for DeepSeek Harness (DSH) maintained by YooRarely, designed to provide convenient access to the Workspace root directory within the DSH Web GUI. The plugin adheres to the MIT license and operates via the public Client Connection Host RPC and Header Slot, without modifying or depending on the DSH source code. Its core features include adding a folder button to the right of the session title and adding an "Open in Explorer" option to the Workspace menu, which allows users to invoke the DSH host command to directly open the current Workspace root directory upon clicking. The plugin supports Windows, macOS, Linux, and WSL platforms, and...