feat: Add core application and marketing layouts, including navigation, user management, and a shared footer component.

src/app/(marketing)/layout.tsx

@@ -150,12 +150,9 @@ export default function MarketingLayout({
           <div className="border-t border-gray-800 mt-8 pt-8 flex items-center justify-between text-gray-400">
             <Link
               href="/newsletter"
-              className="text-xs hover:text-white transition-colors flex items-center gap-1.5 opacity-50 hover:opacity-100"
+              className="text-[6px] text-gray-700 opacity-[0.25] hover:opacity-100 hover:text-white transition-opacity duration-300"
             >
-              <svg className="w-3 h-3" fill="none" stroke="currentColor" viewBox="0 0 24 24">
-                <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M12 15v2m-6 4h12a2 2 0 002-2v-6a2 2 0 00-2-2H6a2 2 0 00-2 2v6a2 2 0 002 2zm10-10V7a4 4 0 00-8 0v4h8z" />
-              </svg>
-              Admin
+              •
             </Link>
             <p>&copy; 2025 QR Master. All rights reserved.</p>
             <div className="w-12"></div>