chore(tailwind): setup Tailwind CSS with preflight on

- Install tailwindcss, postcss, autoprefixer
- Add tailwind.config.js and postcss.config.js
- Create src/styles/tailwind.css with base/components/utilities
- Import Tailwind before index.css in main.tsx

tailwind.config.js

@@ -0,0 +1,12 @@
+/** @type {import('tailwindcss').Config} */
+export default {
+  content: [
+    './index.html',
+    './src/**/*.{ts,tsx}',
+  ],
+  theme: {
+    extend: {},
+  },
+  plugins: [],
+}
+