Stop the subagent-option E2E from waiting on a model response

The factory awaited its subagent to completion, so the test hung wherever no cached model response exists and timed out at 30s on CI. Only the runtime's acceptance of the option payload is under test, and a refused request rejects before a subagent starts. The factory now races the call against a short timer and returns as soon as the request is accepted.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Copilot-Session: 5ece6b29-8b10-47aa-ab17-b64c47f5fdcd

Author: MRayermannMSFT

nodejs/test/e2e/factory.e2e.test.ts

@@ -108,7 +108,10 @@ it.skipIf(isInProcessTransport)(
             status: "completed",
             result: { didThrow: false },
         });
-    }
+    },
+    // The factory abandons its subagent once the runtime has accepted the
+    // request, so the run settles only after the runtime drains that work.
+    60_000
 );
 
 it.skipIf(isInProcessTransport)(

nodejs/test/e2e/fixtures/factory-extension.mjs

@@ -38,15 +38,30 @@ const forwardsSubagentOptions = defineFactory({
         phases: [],
     },
     run: async ({ agent }) => {
+        // Only the runtime's acceptance of the payload is under test. A refused
+        // request rejects quickly, because the runtime parses the options before
+        // it starts a subagent. A subagent that is merely slow to reach a model
+        // proves the payload was accepted, so waiting for it adds nothing and
+        // hangs wherever no model is reachable.
+        const call = agent("Confirm that this request is accepted.", {
+            agent: "reviewer",
+            reasoningEffort: "high",
+            contextTier: "long_context",
+        });
+        // A rejection that lands after the race still needs a handler.
+        call.catch(() => {});
+        let settleTimer;
+        const stillPending = new Promise((resolve) => {
+            settleTimer = setTimeout(() => resolve(undefined), 3000);
+            settleTimer.unref?.();
+        });
         try {
-            await agent("Confirm that this request is accepted.", {
-                agent: "reviewer",
-                reasoningEffort: "high",
-                contextTier: "long_context",
-            });
+            await Promise.race([call, stillPending]);
             return { didThrow: false };
         } catch {
             return { didThrow: true };
+        } finally {
+            clearTimeout(settleTimer);
         }
     },
 });