ci: deploy Pages through GitHub Actions

[Inmerson]

Summary

• replace legacy generated-site commits with native GitHub Pages Actions deployment
• deploy the verified Vite dist artifact at /Math-Biotech-Project/
• preserve /Math-Biotech-Project/site/ with a redirect to the canonical root
• reduce workflow permission from contents: write to read-only contents plus Pages/OIDC deployment permissions
• prevent manual dispatches from deploying non-main refs

Validation

• Node 22 typecheck passed
• Vitest: 5/5 files, 12/12 tests passed
• production Pages build passed
• generated root assets use /Math-Biotech-Project/assets/...
• generated /site/ redirect exists and preserves query/hash
• Vite preview returned HTTP 200 for both canonical and legacy paths
• npm audit: 0 vulnerabilities
• YAML parse and git diff checks passed

Cutover

GitHub Pages is currently �uild_type: legacy. After this PR is green, Pages settings will be switched to workflow immediately before merge so the merge-triggered deployment uses this workflow.

[chatgpt-codex-connector]

You have reached your Codex usage limits for code reviews. You can see your limits in the Codex usage dashboard.
To continue using code reviews, you can upgrade your account or add credits to your account and enable them for code reviews in your settings.

[Copilot]

Copilot was unable to review this pull request because the user who requested the review has reached their quota limit.