test: stabilize gateway ports and timers

test/setup.ts

@@ -1,4 +1,10 @@
 import { installTestEnv } from "./test-env";
+import { afterEach, vi } from "vitest";
 
 const { cleanup } = installTestEnv();
 process.on("exit", cleanup);
+
+afterEach(() => {
+  // Guard against leaked fake timers across test files/workers.
+  vi.useRealTimers();
+});