feat: admit Chongqing real-source metadata baseline

[zhouning]

Summary

• add a path-free, content-addressed, metadata-only admission manifest for the full Chongqing real-source corpus
• bind the original ZIP, the divergent extracted working set, 11 source groups and 16 asset profiles while retaining 57 governance blockers
• add fail-closed validation, focused tests, ADR-074, roadmap/System-of-Record updates and required-platform CI coverage

Evidence boundary

• archive: 533 files, 468,462,251 bytes, SHA-256 2043b60c2f4f7f32a31388a634fae4ac28534990e205aa86b8df0e4b64dcbbca
• extracted working set: 584 files, 700,610,744 bytes, payload SHA-256 e7e81e4f53f9f174792f500fbfdfde6bee30ec03beac8cbd91771fe09f548ea6
• archive/extracted comparison: 526 exact, 6 modified, 0 missing, 52 additional
• checked evidence SHA/file SHA: a2196495d845d61be939c7fc36a7f05c3567e365599d2d04be0aab9c568459c1 / 9b5c20369c235f7e0a2f2cb0a21cee77f86981aa273bac196605a4803b05ce83
• no source payload, local absolute path, record value, geometry or credential is committed
• content admission, publication, scheduler submission, provider mutation, production ingestion and production readiness remain false

Verification

• 10 passed focused admission tests
• 929 passed, 9 warnings Platform Required Tests
• Ruff check and format check
• Python compile, Bash syntax/executable and CI YAML parse
• checked evidence validator, path scan and sensitive-field scan

Closes #52