rickub-registry 0.1.0

OCI distribution-spec v1.1 container registry (registry.rickub.com).

• API endpoint: /v2/ (docker/podman/oras/crane compatible)
• Health: /healthz (liveness), /readyz (catalog + blob store reachable)
• Metrics: /metrics

Architecture & decisions: container-registry.md (docs/architecture/container-registry.md in the repo).