The Docker smoke-test ran the server container under the fixed name
familiar-smoke. On the self-hosted runner the job shares the host
Docker daemon, so a container left behind by a killed or re-run job
(or a concurrent dev push + PR) collides on that name and 'docker run'
fails with exit 125.
Derive the name from the commit SHA, remove any stale container of that
name before starting, and thread the name through the smoke-test and
cleanup steps.
Latte