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/package.json

@@ -0,0 +1,26 @@
+{
+  "name": "spelljammer-web",
+  "version": "1.0.0",
+  "private": true,
+  "type": "module",
+  "scripts": {
+    "dev": "vite",
+    "build": "tsc -b && vite build",
+    "preview": "vite preview"
+  },
+  "dependencies": {
+    "react": "^19.0.0",
+    "react-dom": "^19.0.0",
+    "react-router-dom": "^7.2.0",
+    "zustand": "^5.0.3",
+    "socket.io-client": "^4.8.1",
+    "react-markdown": "^9.0.3"
+  },
+  "devDependencies": {
+    "typescript": "^5.7.3",
+    "vite": "^6.1.0",
+    "@vitejs/plugin-react": "^4.3.4",
+    "@types/react": "^19.0.0",
+    "@types/react-dom": "^19.0.0"
+  }
+}