Align GitHub Pages deployment workflow with the supported Pages setup

[Copilot]

The deploy Actions job was timing out while the Pages deployment remained stuck in deployment_queued. This change updates the workflow to use GitHub’s standard Pages configuration so the uploaded artifact is deployed through the expected setup path.

• Pages workflow configuration

  • add explicit workflow-level permissions required for Pages deployments:
    • contents: read
    • pages: write
    • id-token: write

• Pages environment setup

  • add actions/configure-pages@v5 before artifact upload in build_latex
  • keep the existing LaTeX build and artifact upload flow unchanged

• Scope

  • workflow-only change in .github/workflows/BuildPDFs.yml
  • no changes to PDF generation scripts or course content

permissions:
  contents: read
  pages: write
  id-token: write

# ...

- name: Set up GitHub Pages
  uses: actions/configure-pages@v5