Adds Node setup, an Astro site build, and a wrangler Pages deploy step
to the existing docs workflow, gated on docs/site/** via the paths
trigger. Also fixes astro.config.mjs's site: URL to match the
fish-config-docs Cloudflare Pages project name (it previously pointed
at fish-config.pages.dev, which is not the project being deployed).
Scaffold docs/site/ via `npm create astro@latest ... --template
starlight`. Extend the docs collection schema in
src/content.config.ts with the four custom frontmatter fields (man,
site, manTitle, helpKeywords) needed by the generator in a later
task, using z.strictObject so unrecognized keys fail the build
instead of being silently stripped by Zod's default behavior.
Ignore generated site output (node_modules, dist, .astro, generated
content, and sidebar.json) in .gitignore.
rootiest