Fix public roadmap links

[offalexjackson777-stack]

What changed

• make the GitHub Project number canonical governance data
• derive the exact public roadmap URL in README and generated governance views
• include the project identity in the reviewed GitHub experience and sync plans
• add governance coverage for the project number and URL

Why

The generic repository /projects route returns HTTP 400 to signed-out visitors even though the linked GitHub Project is public. The front door now links directly to the stable public project.

Verification

• .venv/bin/python -m unittest tests.test_governance
• .venv/bin/python -m unittest tests.test_portal tests.test_portal_state
• deterministic ./hfx generate rerun with an unchanged diff
• ./hfx docs build and ./hfx docs verify
• exact public Project URL returns HTTP 200

The change-aware local verifier's governance contracts passed. Its broader run was blocked only by the known host setuptools pin mismatch; hosted CI uses the repository's pinned environment.

[offalexjackson777-stack]

Superseded by the GitHub-native repository navigation and canonical Roadmap link merged in #10. The replacement passed the current required checks.