Refresh personal page from updated Jekyll site

[glrs]

Summary

• Import the updated Jekyll personal site source without committing generated _site output.
• Refresh site identity, navigation, homepage tagline, metadata, and project/blog structure.
• Preserve legacy post URLs for Disqus by setting explicit disqus_url values and adding redirects from old published paths.
• Add a GitHub Actions Jekyll build check using a Ruby 2.7 container compatible with the current lockfile.

Validation

• Served locally on the VM and reviewed in the browser.
• GitHub Actions build passed on branch commit 73ba7d4.

Rollback / safety notes

• The old live site is preserved at branch backup/live-before-personal-page-update.
• The old live site is also preserved at tag live-before-personal-page-update.
• Disqus comments may only fully validate once the site is live at https://glrs.github.io.