Same protocol as ed2f4a1/worker-v0.3.0: the image bakes chain.toml and
cannot contain its own digest, so the tagged build commit carries an
empty pin. The follow-up commit re-pins to the CI-reported digest.
Tag worker-v0.3.1 HERE.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>