feat(ui): detach a monitor into its own window

src/ClaudeDo.Ui/ViewModels/MissionControlViewModel.cs

@@ -33,6 +33,10 @@ public sealed partial class MissionControlViewModel : ViewModelBase, IDisposable
         }
     }
 
+    // View-layer seam: show a detached monitor in its own window. Second arg is the re-dock callback
+    // invoked when that window closes.
+    public Action<TaskMonitorViewModel, Action>? ShowDetached { get; set; }
+
     public bool HasMonitors => Monitors.Count > 0;
 
     public MissionControlViewModel(IDbContextFactory<ClaudeDoDbContext> dbFactory, IWorkerClient worker)
@@ -65,10 +69,24 @@ public sealed partial class MissionControlViewModel : ViewModelBase, IDisposable
         var monitor = new TaskMonitorViewModel(_dbFactory, _worker);
         monitor.SetTaskId(taskId);
         monitor.OpenInAppRequested = _openInApp;
+        monitor.DetachRequested = Detach;
         Monitors.Add(monitor);
         _ = HydrateAsync(monitor, taskId);
     }
 
+    private void Detach(TaskMonitorViewModel monitor)
+    {
+        if (!Monitors.Contains(monitor)) return;
+        Monitors.Remove(monitor);            // drop from grid — do NOT dispose; it keeps streaming
+        ShowDetached?.Invoke(monitor, () => ReDock(monitor));
+    }
+
+    private void ReDock(TaskMonitorViewModel monitor)
+    {
+        if (!Monitors.Contains(monitor) && monitor.SubscribedTaskId is not null)
+            Monitors.Add(monitor);           // back into the grid
+    }
+
     private async System.Threading.Tasks.Task HydrateAsync(TaskMonitorViewModel monitor, string taskId)
     {
         try