DeepSeek Harness Plugin: dsh-workspace-dir

The `dsh-workspace-dir` plugin is designed to address the pain point of constantly switching windows to view project structure during DeepSeek Harness development. It adds a "Directory" button to the session header, providing a draggable floating panel with adjustable opacity (20% by default) that supports browsing directory hierarchies and opening paths in the system file manager. The plugin automatically saves panel state and follows the new working directory when switching sessions. Note that a source-code runtime environment is required, and a restart is mandatory after installation.