fix(worker): close status-force bypasses on Running tasks

update_task_status Idle/Done, WorkerHub.SetTaskStatus, and the UI's Mark
Done/Cancelled menu items could all force a Running task's status without
going through TaskStateService's guards, leaving its CLI process untracked
and its worktree writes silently dropped. Idle now routes through the
already-guarded TaskStateService.ResetToIdleAsync instead of the repo's
unconditional ResetToManualAsync; Done and SetTaskStatus explicitly reject
Running; the context menu disables both entries with a tooltip while
running. TaskRunner also now logs a warning whenever a terminal transition
(SubmitForChildren/SubmitForReview/Complete/Fail) is rejected instead of
silently discarding the run result. DeleteTask's MCP path gets the same
friendly foreign-key message WorkerHub.DeleteTask already had for a task
with children.

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

@@ -900,6 +900,21 @@ public sealed class ExternalMcpServiceTests : IDisposable
             sut.DeleteTask(task.Id, CancellationToken.None));
     }
 
+    [Fact]
+    public async Task DeleteTask_WithChildren_ThrowsUnderstandableMessage()
+    {
+        var listId = await SeedListAsync();
+        var parent = await SeedTaskAsync(listId, status: TaskStatus.WaitingForChildren);
+        await SeedTaskAsync(listId, status: TaskStatus.Idle, parentId: parent.Id);
+        var sut = BuildSut(CreateQueue());
+
+        var ex = await Assert.ThrowsAsync<InvalidOperationException>(() =>
+            sut.DeleteTask(parent.Id, CancellationToken.None));
+
+        Assert.Contains("child task", ex.Message, StringComparison.OrdinalIgnoreCase);
+        Assert.NotNull(await _tasks.GetByIdAsync(parent.Id));
+    }
+
     [Fact]
     public async Task DeleteTask_NotFound_Throws()
     {
@@ -981,6 +996,35 @@ public sealed class ExternalMcpServiceTests : IDisposable
         Assert.Equal(TaskStatus.WaitingForReview, loaded!.Status);
     }
 
+    [Fact]
+    public async Task UpdateTaskStatus_Idle_OnRunningTask_Throws()
+    {
+        var listId = await SeedListAsync();
+        var task = await SeedTaskAsync(listId, status: TaskStatus.Running);
+        var sut = BuildSut(CreateQueue());
+
+        await Assert.ThrowsAsync<InvalidOperationException>(
+            () => sut.UpdateTaskStatus(task.Id, "Idle", CancellationToken.None));
+
+        var loaded = await _tasks.GetByIdAsync(task.Id);
+        Assert.Equal(TaskStatus.Running, loaded!.Status);
+    }
+
+    [Fact]
+    public async Task UpdateTaskStatus_Done_OnRunningTask_Throws()
+    {
+        var listId = await SeedListAsync();
+        var task = await SeedTaskAsync(listId, status: TaskStatus.Running);
+        var sut = BuildSut(CreateQueue());
+
+        var ex = await Assert.ThrowsAsync<InvalidOperationException>(
+            () => sut.UpdateTaskStatus(task.Id, "Done", CancellationToken.None));
+
+        Assert.Contains("running", ex.Message, StringComparison.OrdinalIgnoreCase);
+        var loaded = await _tasks.GetByIdAsync(task.Id);
+        Assert.Equal(TaskStatus.Running, loaded!.Status);
+    }
+
     private ExternalMcpService NewService() => BuildSut(CreateQueue());
 
     private async Task<string> SeedIdleTask(string title = "t")

tests/ClaudeDo.Worker.Tests/Hub/SetTaskStatusHubTests.cs

@@ -0,0 +1,86 @@
+using ClaudeDo.Data.Models;
+using ClaudeDo.Data.Repositories;
+using ClaudeDo.Worker.Hub;
+using ClaudeDo.Worker.Tests.Infrastructure;
+using Microsoft.AspNetCore.SignalR;
+using Microsoft.EntityFrameworkCore;
+using Xunit;
+using TaskStatus = ClaudeDo.Data.Models.TaskStatus;
+
+namespace ClaudeDo.Worker.Tests.Hub;
+
+public sealed class SetTaskStatusHubTests : IDisposable
+{
+    private readonly DbFixture _db = new();
+
+    public void Dispose() => _db.Dispose();
+
+    private WorkerHub CreateHub()
+    {
+        var factory = _db.CreateFactory();
+        var built = TaskStateServiceBuilder.Build(factory);
+        var broadcaster = new HubBroadcaster(new CapturingHubContext());
+        var hub = new WorkerHub(
+            null!, null!, null!, null!, broadcaster, factory,
+            null!, null!, null!, null!, null!, null!, null!, null!, null!, null!,
+            built.State,
+            null!, null!,
+            null!, new ClaudeDo.Worker.Online.OnlineInboxConfig(), new ClaudeDo.Worker.Online.OnlineTokenStore(),
+            new ClaudeDo.Worker.Runner.PendingQuestionRegistry(), null!);
+        hub.Clients = new FakeHubCallerClients(new RecordingClientProxy());
+        hub.Context = new FakeHubCallerContext();
+        return hub;
+    }
+
+    private async Task<string> SeedTaskAsync(TaskStatus status)
+    {
+        using var ctx = _db.CreateContext();
+        var listId = Guid.NewGuid().ToString();
+        await new ListRepository(ctx).AddAsync(new ListEntity
+        {
+            Id = listId, Name = "L", CreatedAt = DateTime.UtcNow,
+        });
+
+        var taskId = Guid.NewGuid().ToString();
+        await new TaskRepository(ctx).AddAsync(new TaskEntity
+        {
+            Id = taskId, ListId = listId, Title = "T",
+            Status = status, CreatedAt = DateTime.UtcNow, CommitType = "feat",
+        });
+        return taskId;
+    }
+
+    [Fact]
+    public async Task SetTaskStatus_RunningTask_Throws_AndLeavesStatusUnchanged()
+    {
+        var taskId = await SeedTaskAsync(TaskStatus.Running);
+        var hub = CreateHub();
+
+        await Assert.ThrowsAsync<HubException>(() => hub.SetTaskStatus(taskId, "Done"));
+
+        await using var ctx = _db.CreateContext();
+        var task = await ctx.Tasks.FindAsync(taskId);
+        Assert.Equal(TaskStatus.Running, task!.Status);
+    }
+
+    [Fact]
+    public async Task SetTaskStatus_IdleTask_StillSucceeds()
+    {
+        var taskId = await SeedTaskAsync(TaskStatus.Idle);
+        var hub = CreateHub();
+
+        await hub.SetTaskStatus(taskId, "Cancelled");
+
+        await using var ctx = _db.CreateContext();
+        var task = await ctx.Tasks.FindAsync(taskId);
+        Assert.Equal(TaskStatus.Cancelled, task!.Status);
+    }
+
+    [Fact]
+    public async Task SetTaskStatus_Missing_Throws()
+    {
+        var hub = CreateHub();
+
+        await Assert.ThrowsAsync<HubException>(() => hub.SetTaskStatus("does-not-exist", "Done"));
+    }
+}