feat(interactive): host task-based ConPTY sessions in Command Center

Adds an 'Open ConPTY session' entry that fetches a task's launch spec and hosts
an embedded ConPTY terminal as a Mission Control pane, coexisting with the
streamed-log monitor panes (streaming stack untouched). Introduces IMissionControlPane
+ ConPtyPaneViewModel, a non-destructive Panes mirror (Monitors prefix + ConPtySessions
suffix) so unrelated monitor churn never tears down a live terminal, and a grid<->tabs
layout toggle. Launch failures surface via the footer error strip.

src/ClaudeDo.Ui/ViewModels/Islands/TasksIslandViewModel.cs

@@ -819,6 +819,18 @@ public sealed partial class TasksIslandViewModel : ViewModelBase, IDisposable
         catch (Exception ex) { ErrorReported?.Invoke(Loc.T("vm.tasksIsland.runInteractiveFailed", ex.Message)); }
     }
 
+    // Distinct from RunInteractivelyAsync (the old in-app streaming session) — this opens the
+    // task in an embedded ConPTY terminal pane in the Command Center. The shell owns the
+    // Mission Control view model, so this just raises an event for it to act on.
+    public event Action<string>? OpenConPtySessionRequested;
+
+    [RelayCommand]
+    private void OpenConPtySession(TaskRowViewModel? row)
+    {
+        if (row is null) return;
+        OpenConPtySessionRequested?.Invoke(row.Id);
+    }
+
     [RelayCommand]
     private async Task PickUpInTerminalAsync(TaskRowViewModel? row)
     {