空コンポーネントをnullに変更

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

Author: na-trium-144

app/(docs)/default.tsx

@@ -1 +1,3 @@
-export default function EmptyPage() {}
+export default function EmptyPage() {
+  return null;
+}