Adds a remote_desktop integration type and a /api/guacamole websocket
route that drives guacamole-lite's ClientConnection directly (bypassing
its Server class, which would otherwise attach an unfiltered upgrade
listener that conflicts with the existing @fastify/websocket routes).
The frontend RemoteDesktop page renders the Guacamole protocol stream
via guacamole-common-js. Verified end-to-end against a real guacd and
VNC server, including in an actual browser session.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BbJV5nm8KPVH1oNJYKpnoF
