Add a 4th reviewer axis: the squash commit subject must concisely and
accurately summarize the actual changes. A poor/inaccurate message is an
ADVISORY-severity concern, so it drives a corrective re-merge (which rewrites
the message) up to maxReviewPasses, then lands — it never hard-blocks the merge
over a message nit. Structural correctness (task-id prefix + Fusion-Task-Id /
lineage trailers) remains deterministically guaranteed by
ensureCommitTaskMetadata regardless.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
c21b907211