Port website over to Astro

[meenbeese]

Summary

Rewrites the Jython website from Jekyll (Ruby) to Astro, using the official create astro scaffold. The generated site is functionally identical — same pages, same URLs, same look — but the toolchain is more modern, faster, and much easier to work with.

Why

• More modern: Astro is an actively developed, TypeScript-first static site generator with a huge ecosystem. Jekyll is Ruby-based and its GitHub Pages toolchain pinned us to Ruby 3.1 (the current gems crash on newer Ruby).
• Easier to use: A single bun install && bun run dev gets a contributor up and running — no Ruby, no Bundler, no gem version pinning. The old setup required matching a specific Ruby version just to build locally.
• Faster builds: a full build now runs in well under a second.
• Familiar authoring: content stays in plain Markdown with frontmatter, so writing pages is unchanged.
• Better defaults: built-in syntax highlighting, component-based layouts, and hot reload.

Before / After

Before (Jekyll)	After (Astro)

What changed

• Replaced the Jekyll project with an Astro project:
  • src/pages/*.md — the 11 content pages (Markdown + layout frontmatter)
  • src/layouts/BaseLayout.astro — header, nav, footer, and SEO meta (ported from _layouts/default.html)
  • src/components/Navbar.astro + src/data/navbar.ts — dropdown navigation (ported from _includes/navigation.html + _data/navbar.yml)
• Moved static assets into public/ (CNAME, .well-known/atproto-did, images, and the existing slate theme CSS).
• Added astro.config.mjs (site: https://www.jython.org, build.format: 'file' to preserve existing .html URLs, github-light code highlighting).
• Added .github/workflows/deploy.yml using the official withastro/action to build and publish to GitHub Pages on master.
• Committed bun.lock so deployments are reproducible.
• Removed the Jekyll files: _config.yml, _data/, _includes/, _layouts/, Gemfile, Gemfile.lock, _site/, assets/, and the root-level .md files now living in src/pages/.
• Updated README.md with the new build/dev instructions.

Notes

• index.md and jyspecific.md previously used Liquid data lookups (site.data.book, site.data.pydoc); these were resolved to their literal URLs to avoid adding the MDX integration.
• No change to the published URL structure (/download, /news, etc. all still resolve).

How to test

bun install
bun run dev      # preview at http://localhost:4321
bun run build    # outputs to dist/