Splits the work into Tranche A (land now: ADR-021, ADR-016/020
reconciliation, ssh-from-control firewall source, ACCESS.md template,
/check-access command, governance + index wiring) and Tranche B
(build-pending on infra: per-service access__* + rendered ACCESS.md,
/check-access running).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
