The camofox-browser image defaults to port 3000 internally, not 9377.
Without -e CAMOFOX_PORT=9377, the -p 9377:9377 mapping silently fails
because nothing listens on 9377 inside the container.
E2E verified: -p 9377:9377 alone → connection reset,
-p 9377:9377 -e CAMOFOX_PORT=9377 → healthy and functional.