Console (cluster dashboard + admin panel) starts as a background
daemon under marvin on :8090, sharing the same config.toml and SQLite
DB (WAL multi-writer). Forwarded via run.sh and exposed through
tailcat; same login as the server.
tailcat (Tailscale data plane, no control plane) forwards the VM's
web UI and SSH ports to another machine via a stable saved-key
address; outbound-only, so it works through the nested slirp NAT.
marvin