chore: initial project scaffold with Fastify server and Vite React app

Set up monorepo structure with server/ (Fastify + TypeScript) and web/ (React + Vite + TypeScript).
Includes package configs, dev proxy setup, and mobile-first CSS foundation.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

web/src/App.tsx

@@ -0,0 +1,10 @@
+function App() {
+  return (
+    <div className="app">
+      <h1>Spelljammer Ship Tracker</h1>
+      <p>App is running. Routes coming soon.</p>
+    </div>
+  );
+}
+
+export default App;