fix(ui): report and gate ListSettingsModal load failures instead of swallowing them

BeginLoad's fire-and-forget LoadAsync now catches instead of leaving an
unobserved task exception, reports it via the new ErrorReported event
(wired into FlashFooterError like the other modal VMs), and keeps Save
locked so the failure can't clobber list_config with blank fields.
LoadTicketProjectsAsync's empty catch now reports too; behavior for the
dropdown itself is unchanged.

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

@@ -58,6 +58,7 @@ public sealed partial class ListsIslandViewModel : ViewModelBase, IDisposable
         if (row is null || Dialogs is null || _services is null) return;
         var rawId = row.Id.StartsWith("user:", StringComparison.Ordinal) ? row.Id["user:".Length..] : row.Id;
         var vm = _services.GetRequiredService<ListSettingsModalViewModel>();
+        vm.ErrorReported += msg => ErrorReported?.Invoke(msg);
         vm.BeginLoad(rawId, row.Name, row.WorkingDir, row.DefaultCommitType, row.IsManual, row.FindingsTracked, row.IconKey);
         await Dialogs.ShowListSettingsAsync(vm);
         if (vm.Deleted) await LoadAsync();
@@ -408,6 +409,7 @@ public sealed partial class ListsIslandViewModel : ViewModelBase, IDisposable
         if (Dialogs is not null && _services is not null)
         {
             var vm = _services.GetRequiredService<ListSettingsModalViewModel>();
+            vm.ErrorReported += msg => ErrorReported?.Invoke(msg);
             vm.BeginLoad(entity.Id, entity.Name, entity.WorkingDir, entity.DefaultCommitType, entity.IsManual, entity.FindingsTracked, entity.Icon);
             await Dialogs.ShowListSettingsAsync(vm);
             if (!vm.Saved && !vm.Deleted)