src/io/watchFile.test.ts flaky test on refactor branch.

[Hweinstock]

src/io/watchFile.test.ts:
  24 |   watchFile(path, () => calls++, controller.signal);
  25 | 
  26 |   writeFileSync(path, '{"a":1}');
  27 |   writeFileSync(path, '{"a":2}');
  28 |   await Bun.sleep(250);
  29 |   expect(calls).toBe(1);
                       ^
  error: expect(received).toBe(expected)
  
  Expected: 1
  Received: 0
  
        at <anonymous> (/Users/runner/work/agentcore-cli/agentcore-cli/src/io/watchFile.test.ts:29:17)
  
  Error: Expected: 1
  Received: 0
  
        at <anonymous> (/Users/runner/work/agentcore-cli/agentcore-cli/src/io/watchFile.test.ts:29:17)
  (fail) debounces a burst of edits into a single callback and stops on abort [257.78ms]
  (pass) a missing file fails quietly rather than throwing [0.18ms]

Ex. https://github.com/aws/agentcore-cli/actions/runs/33117797255/job/98676836925

Seen it fail twice on MacOS, retrying fixed.