add persisted pi workflow extension

extensions/shared/child-session.test.ts

@@ -20,6 +20,7 @@ import {
   createChildResources,
   resolveStandaloneChildProjectTrust,
   shutdownAndDisposeChildSession,
+  waitForChildOperation,
   type DisposableChildSession,
 } from "./child-session.ts";
 
@@ -105,6 +106,7 @@ test("child denylist keeps extension and workflow structured tools available", a
         "subagent_check",
         "subagent_list",
         "workflow",
+        "pi_workflow",
         "ask_user",
       ],
     );
@@ -253,6 +255,12 @@ test("shutdown helper balances hooks and disposal despite errors", async () => {
   assert.equal(disposals, 1);
 });
 
+test("child operations are bounded independently of teardown", async () => {
+  const startedAt = Date.now();
+  await waitForChildOperation(new Promise(() => {}), 5);
+  assert.ok(Date.now() - startedAt < 100);
+});
+
 test("shutdown helper bounds a stuck hook before disposal", async () => {
   let disposals = 0;
   const session: DisposableChildSession = {