Added redirect page

src/app/r/[slug]/not-found.tsx

@@ -0,0 +1,21 @@
+export default function NotFound() {
+    return (
+        <div className="flex min-h-screen items-center justify-center">
+            <div className="text-center">
+                <h1 className="text-6xl font-bold text-gray-900 dark:text-gray-100">404</h1>
+                <h2 className="mt-4 text-2xl font-semibold text-gray-700 dark:text-gray-300">
+                    Link Not Found
+                </h2>
+                <p className="mt-2 text-gray-600 dark:text-gray-400">
+                    The link you're looking for doesn't exist or has expired.
+                </p>
+                <a
+                    href="/"
+                    className="mt-6 inline-block rounded-lg bg-blue-600 px-6 py-3 text-white hover:bg-blue-700 transition-colors"
+                >
+                    Go Home
+                </a>
+            </div>
+        </div>
+    )
+}