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/Services/Interfaces/IWorkerClient.cs

@@ -74,8 +74,6 @@ public interface IWorkerClient : INotifyPropertyChanged
     Task<MergeResultDto> ContinueConflictMergeAsync(string taskId);
     Task AbortConflictMergeAsync(string taskId);
     Task StartPlanningSessionAsync(string taskId, CancellationToken ct = default);
-    // Picks up a task's Claude session in a real terminal window (--resume).
-    Task ResumeTaskInTerminalAsync(string taskId, CancellationToken ct = default);
     /// <summary>Commits an interactively-worked task's worktree and moves it to WaitingForReview
     /// (the only path that flips a hand-driven ConPTY session into the review/merge pipeline).</summary>
     Task SubmitTaskForReviewAsync(string taskId, CancellationToken ct = default);