Cleanup now runs only after the brain schedule is committed or confirmed present. Unreadable and malformed schedule files return non-zero with every legacy artifact intact, so MAINT_RETRY_ON_NEXT_START can retry safely on the next start. Also keep the brain-health cutover guard from flagging its own provider-check detection logic, remove the unused brain_exit_status() helper, and delete the dead agents.json fixture. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>