Fix ultrawide layout: Tailwind was not generating max-width classes.

Move width utilities into scanned components as literal class names, add lib to Tailwind content and safelist. Verified max-w-4xl in build CSS and /learn HTML.

Co-authored-by: Cursor <cursoragent@cursor.com>

tailwind.config.ts

@@ -1,7 +1,12 @@
 /** @type {import('tailwindcss').Config} */
 module.exports = {
   darkMode: ["class"],
-  content: ["./components/**/*.{ts,tsx}", "./app/**/*.{ts,tsx}"],
+  content: [
+    "./app/**/*.{ts,tsx}",
+    "./components/**/*.{ts,tsx}",
+    "./lib/**/*.{ts,tsx}",
+  ],
+  safelist: ["max-w-3xl", "max-w-4xl"],
   theme: {
     container: {
       center: true,