Add data code hosting manifest guard

[shaiananvari8]

summary

• adds data-code-hosting-manifest-guard for scibase issue Scientific/Engineering Data & Code Hosting #14.
• • checks fair metadata, artifact registration, sha-256 hashes, access and embargo state, execution environment, reproducibility commands, and versioning before publication.
• • adds reviewer reports and demo-transcript evidence under data-code-hosting-manifest-guard/reports.

verification

• npm run check passed.
• • npm test passed 4 tests.
• • npm run demo produced status block_publication and digest 777f3022d220fed8225ca1f9586d09274e35b149e2cd764a753769c72c8dd951.

safety

synthetic manifests only. no credentials, private projects, external apis, storage writes, doi issuance, uploads, or repository mutations.

/claim #14

[shaiananvari8]

/claim #14

Validation note for this PR:

• Scope: data-code-hosting-manifest-guard for SCIBASE issue Scientific/Engineering Data & Code Hosting #14.
• Evidence: synthetic reviewer packet, Markdown report, and SVG summary under data-code-hosting-manifest-guard/reports/.
• Local checks: npm run check, npm test, npm run demo.
• Safety: synthetic manifests only; no credentials, private projects, external APIs, storage writes, DOI issuance, or repository mutations.