Fix Tailwind config: add @tailwindcss/vite plugin and use bun server for production

- Add @tailwindcss/vite plugin for proper Tailwind processing
- Change 'start' script from 'vite preview' to 'bun server.ts' (production-ready)
- Remove postcss.config.mjs (handled by Vite plugin)
- server.ts already configured to serve from dist/ directory

Co-Authored-By: Claude Sonnet 4.5 (1M context) <noreply@anthropic.com>

package.json

@@ -5,10 +5,11 @@
   "private": true,
   "scripts": {
     "dev": "vite",
-    "start": "vite preview",
+    "start": "bun server.ts",
     "build": "vite build"
   },
   "devDependencies": {
+    "@tailwindcss/vite": "^4.1.18",
     "@types/bun": "latest",
     "@types/react": "^19.2.8",
     "@types/react-dom": "^19.2.3",