auth/gateway, auth/users, and test/example-service were referencing
images without a registry prefix, causing k8s to fall back to Docker Hub
(which doesn't have these images).
Also generalises the gitea-registry imagePullSecret to all app namespaces
(auth, finance, home, test) via a for_each in Terraform.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
