test(worker): poll for terminal state in the registration-race tests instead of fixed delays

tests/ClaudeDo.Worker.Tests/Services/QueueServiceTests.cs

@@ -671,7 +671,9 @@ public sealed class QueueServiceTests : IDisposable
 
         // The picker's retry must have registered the CTS actually driving this run.
         Assert.True(service.CancelTask(task.Id));
-        await Task.Delay(200);
+        var deadline = DateTime.UtcNow + TimeSpan.FromSeconds(10);
+        while (!cancelled && DateTime.UtcNow < deadline)
+            await Task.Delay(25);
         Assert.True(cancelled);
 
         cts.Cancel();
@@ -696,13 +698,19 @@ public sealed class QueueServiceTests : IDisposable
         await service.StartAsync(cts.Token);
         _waker.Wake();
 
-        // Max retry window is 10 * 20ms; give it comfortable headroom.
-        await Task.Delay(600);
+        // The retry window is 10 * 20ms of Task.Delay, but under full-suite load those delays
+        // stretch — poll for the terminal state instead of guessing a fixed headroom.
+        TaskEntity? reloaded = null;
+        var deadline = DateTime.UtcNow + TimeSpan.FromSeconds(10);
+        while (DateTime.UtcNow < deadline)
+        {
+            reloaded = await _taskRepo.GetByIdAsync(task.Id);
+            if (reloaded!.Status == TaskStatus.Failed) break;
+            await Task.Delay(25);
+        }
         cts.Cancel();
 
         Assert.Equal(0, fake.CallCount);
-
-        var reloaded = await _taskRepo.GetByIdAsync(task.Id);
         Assert.Equal(TaskStatus.Failed, reloaded!.Status);
 
         // The still-registered "other" run must be untouched.