perf(test): speed up suites and reduce fs churn

src/infra/transport-ready.test.ts

@@ -1,6 +1,17 @@
 import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
 import { waitForTransportReady } from "./transport-ready.js";
 
+// Perf: `sleepWithAbort` uses `node:timers/promises` which isn't controlled by fake timers.
+// Route sleeps through global `setTimeout` so tests can advance time deterministically.
+vi.mock("./backoff.js", () => ({
+  sleepWithAbort: async (ms: number) => {
+    if (ms <= 0) {
+      return;
+    }
+    await new Promise<void>((resolve) => setTimeout(resolve, ms));
+  },
+}));
+
 describe("waitForTransportReady", () => {
   beforeEach(() => {
     vi.useFakeTimers();
@@ -16,7 +27,8 @@ describe("waitForTransportReady", () => {
     const readyPromise = waitForTransportReady({
       label: "test transport",
       timeoutMs: 220,
-      logAfterMs: 60,
+      // Deterministic: first attempt at t=0 won't log; second attempt at t=50 will.
+      logAfterMs: 1,
       logIntervalMs: 1_000,
       pollIntervalMs: 50,
       runtime,
@@ -29,9 +41,7 @@ describe("waitForTransportReady", () => {
       },
     });
 
-    for (let i = 0; i < 3; i += 1) {
-      await vi.advanceTimersByTimeAsync(50);
-    }
+    await vi.advanceTimersByTimeAsync(200);
 
     await readyPromise;
     expect(runtime.error).toHaveBeenCalled();
@@ -48,8 +58,9 @@ describe("waitForTransportReady", () => {
       runtime,
       check: async () => ({ ok: false, error: "still down" }),
     });
+    const asserted = expect(waitPromise).rejects.toThrow("test transport not ready");
     await vi.advanceTimersByTimeAsync(200);
-    await expect(waitPromise).rejects.toThrow("test transport not ready");
+    await asserted;
     expect(runtime.error).toHaveBeenCalled();
   });