`docker compose up` failed with "port is already allocated": 3000 was
taken by an unrelated project on the same machine. Publishing it was
never needed — in production the only thing that has to reach this
service is the reverse proxy, which does so over the compose network as
`landing:3000`.
`expose` replaces `ports`, and a commented `ports` block stays for the
cases that do want a host binding. LANDING_PORT is kept but re-labelled
as only mattering then.
Verified: the container binds nothing on the host, answers 200 with the
full page from another container on the network, and stays healthy —
its health check was always internal.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
