fix(studio): move AI generation behind short-lived job requests

test/studio-ai.test.ts

@@ -319,3 +319,91 @@ test("a retry followed by an invalid design does not spend a third request or mi
   expect(batch.diagnostics[0].code).toBe("WRN-STUDIO-PROPOSAL");
   expect(batch.diagnostics[0].message).toContain("schema");
 });
+
+test("async generation acknowledges immediately and polling retrieves the validated batch", async () => {
+  let finish!: () => void;
+  let entered!: () => void;
+  const started = new Promise<void>((resolve) => {
+    entered = resolve;
+  });
+  const blocked = new Promise<void>((resolve) => {
+    finish = resolve;
+  });
+  const handler = studioAI(
+    "test-secret",
+    mockFetch(async () => {
+      entered();
+      await blocked;
+      return completion();
+    }),
+  );
+  const original = await request();
+  const headers = new Headers(original.headers);
+  headers.set("prefer", "respond-async");
+  const accepted = await handler(new Request(original, { headers }));
+  expect(accepted!.status).toBe(202);
+  const { job } = await accepted!.json();
+  await started;
+  const url = `https://components.example/design-studio/api/generate/jobs/${job.id}`;
+  expect((await (await handler(new Request(url)))!.json()).status).toBe(
+    "pending",
+  );
+  expect(
+    (await handler(
+      new Request(url, { headers: { origin: "https://other.example" } }),
+    ))!.status,
+  ).toBe(403);
+  finish();
+  let result: any;
+  for (let i = 0; i < 50; i++) {
+    result = await (await handler(new Request(url)))!.json();
+    if (result.status !== "pending") break;
+    await Bun.sleep(10);
+  }
+  expect(result.status).toBe("complete");
+  expect(result.result.alternatives).toHaveLength(3);
+  expect(
+    (await handler(
+      new Request(url.replace(job.id, "00000000-0000-4000-8000-000000000000")),
+    ))!.status,
+  ).toBe(410);
+});
+
+test("background generation cancellation aborts the provider and leaves no proposals", async () => {
+  let entered!: () => void;
+  const started = new Promise<void>((resolve) => {
+    entered = resolve;
+  });
+  let aborted = false;
+  const handler = studioAI(
+    "test-secret",
+    mockFetch(async (_url, init) => {
+      entered();
+      return await new Promise<Response>((_, reject) => {
+        init!.signal!.addEventListener(
+          "abort",
+          () => {
+            aborted = true;
+            reject(new DOMException("cancelled", "AbortError"));
+          },
+          { once: true },
+        );
+      });
+    }),
+  );
+  const original = await request();
+  const headers = new Headers(original.headers);
+  headers.set("prefer", "respond-async");
+  const { job } = await (await handler(
+    new Request(original, { headers }),
+  ))!.json();
+  await started;
+  const response = await handler(
+    new Request(
+      `https://components.example/design-studio/api/generate/jobs/${job.id}`,
+      { method: "DELETE" },
+    ),
+  );
+  expect((await response!.json()).status).toBe("cancelled");
+  expect(aborted).toBe(true);
+});