move app to app/ subdir

app/src/pages/index.tsx

@@ -0,0 +1,15 @@
+import { type GetServerSideProps } from "next";
+
+// eslint-disable-next-line @typescript-eslint/require-await
+export const getServerSideProps: GetServerSideProps = async () => {
+  return {
+    redirect: {
+      destination: "/experiments",
+      permanent: false,
+    },
+  };
+};
+
+export default function Home() {
+  return null;
+}