feat: separate current and "new" web in route groups

app/[lang]/(preview-current)/error.tsx

@@ -0,0 +1,9 @@
+"use client"
+
+export default function Error({ error }: { error: Error }) {
+  return (
+    <div>
+      <h2>Something went wrong!</h2>
+    </div>
+  )
+}