feat(ui): pick up a task's session in a terminal

tests/ClaudeDo.Worker.Tests/UiVm/TasksIslandViewModelPlanningTests.cs

@@ -70,6 +70,9 @@ sealed class FakeWorkerClient : IWorkerClient
     public Task WakeQueueAsync() { WakeQueueCalls++; return Task.CompletedTask; }
     public Task StartPlanningSessionAsync(string taskId, CancellationToken ct = default) { StartPlanningCalls++; return Task.CompletedTask; }
     public Task OpenInteractiveTerminalAsync(string taskId, CancellationToken ct = default) => Task.CompletedTask;
+    public int PickUpInTerminalCalls { get; private set; }
+    public string? LastPickUpTaskId { get; private set; }
+    public Task ResumeTaskInTerminalAsync(string taskId, CancellationToken ct = default) { PickUpInTerminalCalls++; LastPickUpTaskId = taskId; return Task.CompletedTask; }
     public Task QueuePlanningSubtasksAsync(string parentTaskId, CancellationToken ct = default) => Task.CompletedTask;
     public Task ResumePlanningSessionAsync(string taskId, CancellationToken ct = default) { ResumePlanningCalls++; return Task.CompletedTask; }
     public Task<DiscardPlanningOutcome> DiscardPlanningSessionAsync(string taskId, bool dequeueQueuedChildren = false, CancellationToken ct = default)
@@ -177,6 +180,28 @@ public class TasksIslandViewModelPlanningTests
         PlanningPhase phase = PlanningPhase.None)
         => new TaskRowViewModel { Id = id, Status = status, ParentTaskId = parentId, PlanningPhase = phase };
 
+    [Fact]
+    public async Task PickUpInTerminal_InvokesWorkerWithTaskId()
+    {
+        var row = MakeRow("t1", TaskStatus.WaitingForReview);
+        var (vm, worker) = VmFactory.Create([row]);
+
+        await vm.PickUpInTerminalCommand.ExecuteAsync(row);
+
+        Assert.Equal(1, worker.PickUpInTerminalCalls);
+        Assert.Equal("t1", worker.LastPickUpTaskId);
+    }
+
+    [Fact]
+    public void CanPickUpInTerminal_OnlyForReviewOrFailed()
+    {
+        Assert.True(MakeRow("a", TaskStatus.WaitingForReview).CanPickUpInTerminal);
+        Assert.True(MakeRow("b", TaskStatus.Failed).CanPickUpInTerminal);
+        Assert.False(MakeRow("c", TaskStatus.Idle).CanPickUpInTerminal);
+        Assert.False(MakeRow("d", TaskStatus.Running).CanPickUpInTerminal);
+        Assert.False(MakeRow("e", TaskStatus.Done).CanPickUpInTerminal);
+    }
+
     [Fact]
     public void PlanningParentWithChildren_CollapsedByDefault_ToggleExpands()
     {