The smoke test probed the server over the network, which fails on the
self-hosted runner: the job step runs in a container that shares the host
Docker socket but sits on a different network, so it can reach neither a
published host port (-p lands on the runner host) nor the server
container's bridge IP (different network → curl connect hangs, so the job
looked stuck rather than failing).
Probe from inside the server container with `docker exec` instead: it goes
through the Docker socket and runs in the server's own netns, where
127.0.0.1:8080 always works regardless of runner topology. The image ships
python + httpx, so no curl or extra image pull is needed. Drop the now
unnecessary -p publish.
Latte