lcgash/dsh-plugin-uw

## Core Features
- The plugin merges one primary directory and one or more member directories into a union workspace that an AI assistant can access within a single DSH session.
- It provides two permission presets: workspace-write, which permits reading, writing, deleting, and moving through the plugin's member-directory tools, and danger-full-access, which allows unrestricted read and write access.
- A sidebar management panel supports creating, deleting, modifying, and browsing union workspaces, with a tree view for member directories that uses lazy loading and recursive expansion.
- Existing sessions can be upgraded to union workspaces through the /uw command or a session-header button, and workspace definitions persist in ~/.dsh/union-workspaces.json.
- Chat input supports @ mentions that search files across member directories, while registered uw_read, uw_write, uw_edit, uw_delete, and uw_move tools operate on member-directory paths outside the standard single-root sandbox.

## Use Cases
- The plugin supports front-end and back-end coordination tasks where code, shared type definitions, and related assets are stored in separate directories.
- It can limit an assistant