Escape hatch for the initial rollout window (canary fleet not yet
provisioned, so canary-verify.yml's automatic promotion doesn't fire)
AND for manual rollback scenarios.
Uses the default GITHUB_TOKEN which carries write:packages on repo-
owned GHCR images, so no new secrets are needed. crane handles the
remote retag without pulling or pushing layers.
Validates the src tag exists before retagging + verifies the :latest
digest post-retag so a typo can't silently promote the wrong image.
Trigger from Actions → promote-latest → Run workflow → enter the
short sha (e.g. "4c1d56e").
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
