Initial commit: installable PWA hello world

React + TypeScript + Tailwind v4 + shadcn/ui frontend (client), Express +
better-sqlite3 backend (server) in a pnpm workspace. Includes vite-plugin-pwa
manifest, service worker, and iOS install meta tags. GET /api/hello increments a
visit counter in SQLite; backend serves the built client in production.

server/.env.example

@@ -0,0 +1,2 @@
+# Port the backend listens on (defaults to 3001)
+PORT=3001