The built-in actions token lacks package registry write scope,
causing docker login to fail with "unauthorized". A PAT with
write:package scope must be added as the REGISTRY_TOKEN secret.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Builds backend and frontend images and pushes them to the Gitea
Container Registry on every push to main.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
