fix(mcp): keep wait_for_task_change waiting through a planning-chain block

tests/ClaudeDo.Worker.Tests/External/TaskWaitMcpToolsTests.cs

@@ -198,23 +198,21 @@ public sealed class TaskWaitMcpToolsTests : IDisposable
     }
 
     [Fact]
-    public async Task WaitForTaskChange_QueuedWithBlockedByTaskId_ReportsBlockedImmediately()
+    public async Task WaitForTaskChange_QueuedWithBlockedByTaskId_KeepsWaiting_BecauseTheChainResolvesItself()
     {
+        // A planning-chain link clears automatically once the predecessor goes terminal, so it
+        // must NOT short-circuit the wait -- otherwise waiting on a queued fan-out returns
+        // instantly for every chained child and the caller burns a turn per poll.
         var predecessor = await SeedTaskAsync(TaskStatus.Queued);
         var task = await SeedTaskAsync(TaskStatus.Queued);
         task.BlockedByTaskId = predecessor.Id;
         await _tasks.UpdateAsync(task);
         var sut = BuildSut();
-        var sw = Stopwatch.StartNew();
 
-        var result = await sut.WaitForTaskChange([task.Id], timeoutSeconds: 30, cancellationToken: CancellationToken.None);
+        var result = await sut.WaitForTaskChange([task.Id], timeoutSeconds: 1, cancellationToken: CancellationToken.None);
 
-        sw.Stop();
-        Assert.False(result.TimedOut);
-        var change = Assert.Single(result.Changed);
-        Assert.Equal("Blocked", change.Status);
-        Assert.Contains(predecessor.Id, change.BlockedReason);
-        Assert.True(sw.Elapsed < TimeSpan.FromSeconds(2), $"took {sw.Elapsed}");
+        Assert.True(result.TimedOut);
+        Assert.Empty(result.Changed);
     }
 
     [Fact]