fix(worker): route done-toggle and dequeue through guarded TaskStateService transitions

The task-list done toggle (both islands) and RemoveFromQueue wrote TaskEntity.Status
directly via EF, bypassing TaskStateService: no TaskUpdated broadcast, no guard against
a concurrent picker claim (lost update), and no status-based filter. Added guarded
MarkDoneAsync/UnmarkDoneAsync/DequeueToIdleAsync transitions plus matching hub methods
(SetTaskDone/UnsetTaskDone/DequeueTask) and IWorkerClient wrappers; the three UI call
sites now route through the hub with optimistic-then-revert row updates and
ErrorReported on failure. RemoveFromQueueAsync dequeues each queued child individually
through the same guarded path instead of cascading via a raw EF update.

Also closes two hub guard gaps: UpdateListConfig's delete branch now preserves a list's
SerializeOnFileOverlap flag instead of dropping it, and SubmitTaskForReview's Idle/Failed
status gate now runs before either mutation branch so a Done/Cancelled task can't get
committed or stamped and then rejected.

tests/ClaudeDo.Worker.Tests/State/TaskStateServiceTests.cs

@@ -477,6 +477,84 @@ public sealed class TaskStateServiceTests : IDisposable
         Assert.Equal(TaskStatus.Running, await GetStatusAsync(id));
     }
 
+    // ─── MarkDoneAsync / UnmarkDoneAsync ─────────────────────────────────
+
+    [Fact]
+    public async Task MarkDoneAsync_FromIdle_TransitionsToDone_AndStampsFinishedAt()
+    {
+        var id = await SeedTaskAsync(TaskStatus.Idle);
+        var now = DateTime.UtcNow;
+
+        var result = await _sut.MarkDoneAsync(id, now, default);
+
+        Assert.True(result.Ok);
+        var t = await GetTaskAsync(id);
+        Assert.Equal(TaskStatus.Done, t.Status);
+        Assert.Equal(now, t.FinishedAt);
+    }
+
+    [Fact]
+    public async Task MarkDoneAsync_FromRunning_Rejects_AndLeavesStatusUnchanged()
+    {
+        var id = await SeedTaskAsync(TaskStatus.Running);
+
+        var result = await _sut.MarkDoneAsync(id, DateTime.UtcNow, default);
+
+        Assert.False(result.Ok);
+        Assert.Equal(TaskStatus.Running, await GetStatusAsync(id));
+    }
+
+    [Fact]
+    public async Task UnmarkDoneAsync_FromDone_TransitionsToIdle()
+    {
+        var id = await SeedTaskAsync(TaskStatus.Done);
+
+        var result = await _sut.UnmarkDoneAsync(id, default);
+
+        Assert.True(result.Ok);
+        Assert.Equal(TaskStatus.Idle, await GetStatusAsync(id));
+    }
+
+    [Fact]
+    public async Task UnmarkDoneAsync_FromRunning_Rejects_AndLeavesStatusUnchanged()
+    {
+        var id = await SeedTaskAsync(TaskStatus.Running);
+
+        var result = await _sut.UnmarkDoneAsync(id, default);
+
+        Assert.False(result.Ok);
+        Assert.Equal(TaskStatus.Running, await GetStatusAsync(id));
+    }
+
+    // ─── DequeueToIdleAsync ───────────────────────────────────────────────
+
+    [Fact]
+    public async Task DequeueToIdleAsync_FromQueued_TransitionsToIdle_AndClearsBlockedByTaskId()
+    {
+        var pred = await SeedTaskAsync(TaskStatus.Queued);
+        var id = await SeedTaskAsync(TaskStatus.Queued, blockedBy: pred);
+
+        var result = await _sut.DequeueToIdleAsync(id, default);
+
+        Assert.True(result.Ok);
+        var t = await GetTaskAsync(id);
+        Assert.Equal(TaskStatus.Idle, t.Status);
+        Assert.Null(t.BlockedByTaskId);
+    }
+
+    [Fact]
+    public async Task DequeueToIdleAsync_FromRunning_Rejects_AndLeavesStatusUnchanged()
+    {
+        // Simulates the picker having already claimed the task between the UI reading
+        // its row and the dequeue call landing.
+        var id = await SeedTaskAsync(TaskStatus.Running);
+
+        var result = await _sut.DequeueToIdleAsync(id, default);
+
+        Assert.False(result.Ok);
+        Assert.Equal(TaskStatus.Running, await GetStatusAsync(id));
+    }
+
     // ─── StartPlanningAsync ───────────────────────────────────────────────
 
     [Fact]