refactor: repartition server-side and client-side code

app/.client/components/upage/Index.tsx

@@ -0,0 +1,11 @@
+import { UPageBrand } from './Brand';
+import { UPageShare } from './Share';
+
+export function UPageIndex() {
+  return (
+    <>
+      <UPageShare />
+      <UPageBrand />
+    </>
+  );
+}