feat(ecommerce): migrate Ari Shopping to Next.js 15 headless storefront v4

workloads/ecommerce/app/api/health/route.ts

@@ -0,0 +1,3 @@
+export function GET() {
+  return Response.json({ status: "ok", service: "ari-shopping-frontend", version: "4.0.0" }, { status: 200 });
+}