chore: add nextjs template

frontend-nextjs/app/page.tsx

@@ -0,0 +1,23 @@
+import Header from "@/components/Header";
+import Footer from "@/components/Footer";
+import ProductCard from "@/components/ProductCard";
+import { fetchProducts } from "@/lib/api";
+
+export default async function Page() {
+  const products = await fetchProducts();
+
+  return (
+    <main>
+      <Header />
+      <section style={{ maxWidth: 1100, margin: "32px auto", padding: "0 24px" }}>
+        <h1 style={{ marginBottom: 16 }}>Featured products</h1>
+        <div style={{ display: "grid", gap: 16, gridTemplateColumns: "repeat(auto-fill, minmax(220px, 1fr))" }}>
+          {products.slice(0, 8).map((product) => (
+            <ProductCard key={product.id} product={product} />
+          ))}
+        </div>
+      </section>
+      <Footer />
+    </main>
+  );
+}