chore: migrate site to vite

[satyaborg]

Problem

Site dev relied on hand-rolled build.mjs/dev.mjs plus three overlapping dev deps (@tailwindcss/cli, browser-sync, serve) and a manual dist/ copy step. Goal: collapse to pnpm i + pnpm dev with no framework.

Approach

Replace the custom plumbing with Vite + @tailwindcss/vite.

• pnpm dev → Vite dev server with HMR (localhost:5173), no dist/ in dev
• pnpm build → vite build emits static dist/
• pnpm preview → vite build && vite preview (always rebuilds, never serves stale/missing output)
• Deleted build.mjs, dev.mjs; dropped browser-sync + serve
• Moved fonts/ → public/fonts/ (served at /fonts/); updated @font-face URLs and the <link> in index.html
• README dev/build/structure sections updated

Vite is a dev server/bundler, not a framework — no runtime added to the output.

Deploy

Unchanged for Cloudflare Pages / any static host: build command pnpm build, output dist.

Test evidence

• pnpm build succeeds; dist/ contains hashed CSS + both .woff2 fonts, CSS references resolve to /fonts/
• Dev server smoke test: HTTP 200 for /, /src/input.css, /fonts/JetBrainsMono-400.woff2