Add project visibility transition guard

[taherdhanera]

/claim #11

Summary

Adds project-visibility-transition-guard, a self-contained User & Project Management slice that checks private, institutional-only, or invitation-only scientific workspaces before public visibility changes are applied.

The guard evaluates:

• required owner, data-steward, and institution-admin approvals
• collaborator consent for public profile exposure
• object-level document/code/data permissions
• restricted datasets, human-derived data, anonymous-review comments, and other sensitive labels
• object public-readiness flags and owner attribution
• active IRB/funder holds
• external partner access and redistribution risk
• immutable transition audit evidence

Non-overlap

This is not a broad workspace/RBAC ledger, privacy access review, identity recovery guard, member lifecycle/offboarding flow, institutional recertification, anonymous-review escrow, identity merge/export, data-room consent ledger, researcher profile sync, archive handoff, access-audit anomaly monitor, role delegation guard, invitation-domain/MFA guard, funding-attribution guard, service-token governance guard, deletion/erasure guard, break-glass access guard, or contribution-credit gate. It focuses specifically on safe public visibility transitions.

Local validation

Run from project-visibility-transition-guard/:

npm run check
npm test
npm run demo
npm run demo:video

All four commands passed locally.

Reviewer artifacts

• reports/summary.json
• reports/reviewer-packet.md
• reports/summary.svg
• reports/demo.webm

Safety

All data is synthetic. The module does not call OAuth, SAML, ORCID, storage, profile, permission, email, audit-log, or external services. It does not include private project data, credentials, real users, human-subject records, or access-control mutations.