refactor(ui): remove pick-up-in-terminal, keep ConPTY as the single session entry

Two context-menu entries opened a Claude session for the same task via different
mechanisms (embedded ConPTY vs. an external wt terminal). Drop the external-terminal
path entirely, including its worker hub method, launcher plumbing, and localization
keys, since the embedded ConPTY session already covers every case it did.

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

@@ -966,15 +966,6 @@ public sealed partial class TasksIslandViewModel : ViewModelBase, IDisposable
         OpenConPtySessionRequested?.Invoke(row.Id);
     }
 
-    [RelayCommand]
-    private async Task PickUpInTerminalAsync(TaskRowViewModel? row)
-    {
-        if (row is null || _worker is null) return;
-        ForegroundHelper.AllowAny();
-        try { await _worker.ResumeTaskInTerminalAsync(row.Id); }
-        catch (Exception ex) { ErrorReported?.Invoke(Loc.T("vm.tasksIsland.pickUpInTerminalFailed", ex.Message)); }
-    }
-
     [RelayCommand]
     private async Task ResumePlanningSessionAsync(TaskRowViewModel? row)
     {