[WIP] Fix failing GitHub Actions job deploy

[Copilot]

• Inspect failing deploy workflow logs and repository deployment configuration
• Reproduce the relevant build/test state locally
• Implement the smallest workflow or packaging fix for deploy
• Add or update focused validation if appropriate
• Run targeted verification, secret scan, and final validation

[tmolteno]

The docs deployment workflow has been added in commit e41cd5e (.github/workflows/docs.yml). It uses peaceiris/actions-gh-pages@v4 to deploy Doxygen output to GitHub Pages. Closing this WIP PR.