Reconstructs the dockerconfigjson pull secret from the shared /registry v3
fields (GITEA_REGISTRY_USERNAME/GITEA_REGISTRY_TOKEN) via the shared
infisical-operator/infisical-auth. Targets parallel-name
gitea-registry-infisical; old gitea-registry stays live until cutover.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>