Record public repository access

[f-gueguen]

Summary

• mark the external-review repository access blocker closed now that the repository is public
• update manuscript build notes with the public repository URL
• close the hosted-CI validation blocker with the passing Python 3.11/3.12 run

Validation

• Hosted CI passed on Python 3.11 and Python 3.12: https://github.com/lucent-lab/qet-bench/actions/runs/24507308274
• Pandoc smoke builds for paper.md and rescience.md passed locally after the docs edits

Notes

• GitHub emitted a non-blocking Node.js 20 deprecation warning for actions/checkout@v4 and actions/setup-python@v5