fix(ui): Worktrees-Uebersicht zeigt Task-Nummern, DIFF-Spalte trimmt statt abzuschneiden

Befund F7 aus der Sichtpruefung 2026-09-16. TaskNumber war bereits im
WorktreeMaintenanceService-Join und in WorktreeOverviewRow vorhanden, fehlte
aber im Wire-DTO und in der UI-Kette; jetzt bis zur Row-/Conflict-Anzeige
durchgereicht (#<number> dimmed vor dem Titel, ausgeblendet bei 0). DIFF-Spalte
bekommt CharacterEllipsis-Trimming + Tooltip statt hartem Cut, Spalte von 80
auf 110px verbreitert (Header und Row synchron).

src/ClaudeDo.Ui/ViewModels/Modals/WorktreesOverviewModalViewModel.cs

@@ -16,6 +16,7 @@ public enum BatchMergeOutcome { None, Merging, Merged, Conflict, Blocked, Verify
 public sealed partial class WorktreeOverviewRowViewModel : ViewModelBase
 {
     [ObservableProperty] private string _taskId = "";
+    [ObservableProperty] private int _taskNumber;
     [ObservableProperty] private string _taskTitle = "";
     [ObservableProperty][NotifyPropertyChangedFor(nameof(IsRunning))] private TaskStatus _taskStatus;
     [ObservableProperty] private string _listId = "";
@@ -49,6 +50,9 @@ public sealed partial class WorktreeOverviewRowViewModel : ViewModelBase
     public bool IsKept => State == WorktreeState.Kept;
     public bool IsRunning => TaskStatus == TaskStatus.Running;
 
+    // 0 = row without an allocated number (test seeds); a bare "#0" would be meaningless.
+    public bool ShowNumberBadge => TaskNumber > 0;
+
     private static string FormatAge(TimeSpan ts)
     {
         if (ts.TotalDays >= 1) return $"{(int)ts.TotalDays}d ago";
@@ -366,7 +370,7 @@ public sealed partial class WorktreesOverviewModalViewModel : ViewModelBase
 
     private static WorktreeOverviewRowViewModel Map(WorktreeOverviewDto d) => new()
     {
-        TaskId = d.TaskId, TaskTitle = d.TaskTitle, TaskStatus = d.TaskStatus,
+        TaskId = d.TaskId, TaskNumber = d.TaskNumber, TaskTitle = d.TaskTitle, TaskStatus = d.TaskStatus,
         ListId = d.ListId, ListName = d.ListName,
         Path = d.Path, BranchName = d.BranchName, BaseCommit = d.BaseCommit, State = d.State,
         DiffStat = d.DiffStat, CreatedAt = d.CreatedAt, PathExistsOnDisk = d.PathExistsOnDisk,