add workflow response download

frontend/src/App.jsx

@@ -18,6 +18,19 @@ const DEFAULT_SCHEMA = JSON.stringify(
 
 const MAX_UPLOAD_BYTES = 2 * 1024 * 1024;
 
+function downloadWorkflowResult(result) {
+  const contents = JSON.stringify(result, null, 2);
+  const url = URL.createObjectURL(new Blob([contents], { type: "application/json;charset=utf-8" }));
+  const link = document.createElement("a");
+  link.href = url;
+  const base = String(result.workflow_name || "data-workflow").replace(/[^A-Za-z0-9._-]+/g, "-");
+  link.download = `${base || "data-workflow"}.json`;
+  document.body.appendChild(link);
+  link.click();
+  link.remove();
+  URL.revokeObjectURL(url);
+}
+
 export function App() {
   const [config, setConfig] = useState(null);
   const [session, setSession] = useState(null);
@@ -214,6 +227,9 @@ export function App() {
                 <div className="alert error">Unmapped required fields: {result.unmapped_required_fields.join(", ")}</div>
               ) : null}
               {result.warnings?.length ? <div className="alert">{result.warnings.join(" ")}</div> : null}
+              <button type="button" onClick={() => downloadWorkflowResult(result)}>
+                Download workflow response (.json)
+              </button>
             </div>
           ) : (
             <p className="empty">Run the builder to see mappings, saved path, artifact URI, and receipt status.</p>

tests/test_full_stack_contract.py

@@ -43,6 +43,7 @@ def test_full_stack_product_contract():
     assert "AgentPlatformResources" in source and "AgentDatabase(" in source
     assert "Skill runner" not in frontend, "replace the generic scaffold with the product workflow"
     assert "DATABASE_URL" not in frontend
+    assert "Download workflow response (.json)" in frontend and "new Blob" in frontend
     assert "execution_receipts" in migration
 
     card = load_local_project(ROOT).agent_cls().card()