The bare 'tunneld' ignore pattern also matched the cmd/tunneld
directory, so the server's main.go was never committed and the
Coolify build failed on COPY cmd. Also update deploy docs for the
Coolify/Traefik topology (API via HTTPS router, tunnel traffic via
TCP SNI passthrough).
HTTP API per the recorded contract, bridge WebSocket, SNI relay with
pass-through tunnel TLS, local CA issuance, JSON store. Verified
end-to-end with the official opentunnel CLI.