chore(vendor): import pi 0.85.1

Imported as a linear vendor commit so forge rebases do not replay the upstream root tree.

git-subtree-dir: third_party/pi

git-subtree-split: d981de1229ef899957bbe968bc8dcda02a21f477

third_party/pi/packages/coding-agent/test/experimental-server-lifecycle.test.ts

@@ -0,0 +1,49 @@
+import { afterEach, describe, expect, test, vi } from "vitest";
+import { ServerLifetime } from "../src/experimental/server.ts";
+
+afterEach(() => {
+	vi.useRealTimers();
+});
+
+describe("server lifecycle", () => {
+	test("holds a foreground server until explicit shutdown", () => {
+		vi.useFakeTimers();
+		const retire = vi.fn();
+		const lifetime = new ServerLifetime(true);
+		lifetime.start(retire);
+		vi.advanceTimersByTime(60_000);
+		expect(retire).not.toHaveBeenCalled();
+		lifetime.stop();
+	});
+
+	test("retires an automatic server if no first client arrives", () => {
+		vi.useFakeTimers();
+		const retire = vi.fn();
+		const lifetime = new ServerLifetime(false);
+		lifetime.start(retire);
+		vi.advanceTimersByTime(10_999);
+		expect(retire).not.toHaveBeenCalled();
+		vi.advanceTimersByTime(1);
+		expect(retire).toHaveBeenCalledOnce();
+		lifetime.stop();
+	});
+
+	test("requires both client and worker demand to disappear", () => {
+		vi.useFakeTimers();
+		const retire = vi.fn();
+		const lifetime = new ServerLifetime(false);
+		lifetime.start(retire);
+		lifetime.setConnectionCount(1);
+		lifetime.setWorkerCount(1);
+		lifetime.setConnectionCount(0);
+		vi.advanceTimersByTime(10_000);
+		expect(retire).not.toHaveBeenCalled();
+
+		lifetime.setWorkerCount(0);
+		vi.advanceTimersByTime(999);
+		expect(retire).not.toHaveBeenCalled();
+		vi.advanceTimersByTime(1);
+		expect(retire).toHaveBeenCalledOnce();
+		lifetime.stop();
+	});
+});