feat: gate Chongqing source governance decisions

[zhouning]

Summary

• add the M3-30 metadata-only governance gate for the first Chongqing land-parcel candidate
• bind M3-28/M3-29 fingerprints and keep all eight governance decisions pending
• add CI/staging parity validation, ADR-077, roadmap and system-of-record updates

Safety boundary

• no source payloads or absolute paths are added
• no Landing, scheduler, provider mutation, production ingestion, or production readiness authority is created

Verification

• 711 required platform tests passed locally
• focused M3-28/M3-29/M3-30 tests passed
• Ruff and git diff --check passed