feat(not-found.tsx): add NotFound component, this might allow next.js…

… to skip a whole renderer process at runtime, because at the moment the 404 page is recognized as a pages app

app/not-found.tsx

@@ -0,0 +1,21 @@
+export default function NotFound() {
+  return (
+    <>
+      <main className="grid min-h-full place-items-center bg-white px-6 py-24 sm:py-32 lg:px-8">
+        <div className="text-center">
+          <p className="text-base font-semibold text-indigo-600">404</p>
+          <h1 className="mt-4 text-3xl font-bold tracking-tight text-gray-900 sm:text-5xl">Page not found</h1>
+          <p className="mt-6 text-base leading-7 text-gray-600">Sorry, we couldn’t find the page you’re looking for.</p>
+          <div className="mt-10 flex items-center justify-center gap-x-6">
+            <a
+              href="/"
+              className="rounded-md bg-indigo-600 px-3.5 py-2.5 text-sm font-semibold text-white shadow-sm hover:bg-indigo-500 focus-visible:outline focus-visible:outline-2 focus-visible:outline-offset-2 focus-visible:outline-indigo-600"
+            >
+              Go back home
+            </a>
+          </div>
+        </div>
+      </main>
+    </>
+  );
+}