addendum 29: D-074 ADOPTED+EXECUTED -- overlap-allowed tenant CIDRs (Phase 0 gates proven live: exact-overlap subnet + Magnum cluster via API-LB), stage-4 guard rewritten with real overlap math (DOCFIX-106), repo_lint L5 numbering print removed (DOCFIX-107), D-016 amended, contract/runbook/intake aligned

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QFdCdEuxynmM8Q6HichbHn