Hub runtime validated on Oracle Always Free via Compose

We need a free, intermittent way to prove the published Docker Hub API images work in a production-shaped environment (#96). We treat staging and production as the same Hub runtime package (backend + worker + Beat + Postgres + Redis; SMTP external; frontend out of scope for now), run it with Docker Compose on Oracle Cloud Always Free, terminate TLS with Caddy at rbac-api.mnfprofile.com, pin image tags by default, and document first-time OCI setup with Created/Last verified dates. Paid always-on VPS and free PaaS were rejected for maintainer validation: VPS costs money we do not want for start/stop testing; free PaaS cannot honestly host an always-on worker plus persistent Redis.