Task 002: add shared domain contracts

apps/frontend/src/app/page.tsx

@@ -1,8 +1,17 @@
+import type { ArticleListResponse } from "@pipeline/shared";
+
+const initialArticles: ArticleListResponse = {
+  articles: [],
+};
+
 export default function HomePage() {
   return (
     <main>
       <h1>AI Content Pipeline</h1>
       <p>Dockerized monorepo foundation is running.</p>
+      <p>
+        {initialArticles.articles.length} articles in the contract-backed dashboard.
+      </p>
     </main>
   );
 }