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.Localization/locales/de.json

@@ -772,7 +772,7 @@
     "sessionSkillsTab": { "installed": "Installiert: {0}", "installFailed": "Installation fehlgeschlagen: {0}", "updated": "Aktualisiert.", "updateFailed": "Aktualisierung fehlgeschlagen: {0}", "removed": "Entfernt.", "removeFailed": "Entfernen fehlgeschlagen: {0}" },
     "worktreesTab": { "workerOffline": "Worker offline.", "removed": "{0} Worktree(s) entfernt.", "blocked": "Zwangsentfernung nicht möglich: {0} Aufgabe(n) laufen noch. Brich sie zuerst ab.", "removedFrom": "{0} Worktree(s) von {1} Aufgabe(n) entfernt.", "cleanupFailed": "Aufräumen fehlgeschlagen: {0}", "resetFailed": "Zurücksetzen fehlgeschlagen: {0}" },
     "worktreesOverview": { "titleAll": "Worktrees", "titleList": "Worktrees — {0}", "listFallback": "Liste", "cleanupFailed": "Aufräumen fehlgeschlagen.", "cleanupFailedDetailed": "Aufräumen fehlgeschlagen: {0}", "removed": "{0} Worktree(s) entfernt.", "discardConfirm": "Worktree für \"{0}\" verwerfen? Nicht committete Arbeit geht verloren.", "discardFailed": "Worktree konnte nicht verworfen werden.", "keepFailed": "Worktree konnte nicht behalten werden.", "cannotForceRunning": "Eine laufende Aufgabe kann nicht zwangsweise entfernt werden.", "forceRemoveFailed": "Zwangsentfernung fehlgeschlagen.", "forceRemoveFailedDetailed": "Zwangsentfernung fehlgeschlagen: {0}", "batchDone": "{0} gemergt, {1} zu lösen.", "openInExplorerFailed": "Pfad konnte nicht geöffnet werden: {0}" },
-    "listSettings": { "untitled": "Unbenannt", "ticketProjectNone": "— keins —" },
+    "listSettings": { "untitled": "Unbenannt", "ticketProjectNone": "— keins —", "loadFailed": "Listeneinstellungen konnten nicht geladen werden: {0}", "ticketProjectsLoadFailed": "Ticket-Projekte konnten nicht geladen werden: {0}" },
     "detailsIsland": { "verifyFailed": "Merge ist erfolgt, aber das Verifikationskommando der Liste ist fehlgeschlagen — die Aufgabe wurde nicht auf 'Erledigt' gesetzt.", "untrackedCollision": "Merge abgelehnt — er würde eine unversionierte Datei im Ziel-Arbeitsverzeichnis überschreiben.", "stopOffline": "Worker offline — Task kann nicht gestoppt werden.", "stopFailed": "Stoppen fehlgeschlagen: {0}", "enqueueFailed": "In die Warteschlange stellen fehlgeschlagen: {0}", "dequeueFailed": "Aus der Warteschlange entfernen fehlgeschlagen: {0}", "resetAndRetryFailed": "Zurücksetzen & erneut versuchen fehlgeschlagen: {0}", "toggleDoneFailed": "Erledigt-Status konnte nicht aktualisiert werden: {0}" },
     "mergeSection": { "openWorktreeFailed": "Worktree konnte nicht geöffnet werden: {0}" },
     "about": { "openPathFailed": "Pfad konnte nicht geöffnet werden: {0}" },

src/ClaudeDo.Localization/locales/en.json

@@ -772,7 +772,7 @@
     "sessionSkillsTab": { "installed": "Installed: {0}", "installFailed": "Install failed: {0}", "updated": "Updated.", "updateFailed": "Update failed: {0}", "removed": "Removed.", "removeFailed": "Remove failed: {0}" },
     "worktreesTab": { "workerOffline": "Worker offline.", "removed": "Removed {0} worktree(s).", "blocked": "Cannot force-remove: {0} task(s) still running. Cancel them first.", "removedFrom": "Removed {0} worktree(s) from {1} task(s).", "cleanupFailed": "Cleanup failed: {0}", "resetFailed": "Reset failed: {0}" },
     "worktreesOverview": { "titleAll": "Worktrees", "titleList": "Worktrees — {0}", "listFallback": "list", "cleanupFailed": "Cleanup failed.", "cleanupFailedDetailed": "Cleanup failed: {0}", "removed": "Removed {0} worktree(s).", "discardConfirm": "Discard the worktree for \"{0}\"? Uncommitted work will be lost.", "discardFailed": "Failed to discard worktree.", "keepFailed": "Failed to keep worktree.", "cannotForceRunning": "Cannot force-remove a running task.", "forceRemoveFailed": "Force remove failed.", "forceRemoveFailedDetailed": "Force remove failed: {0}", "batchDone": "Merged {0}, {1} need resolution.", "openInExplorerFailed": "Couldn't open path: {0}" },
-    "listSettings": { "untitled": "Untitled", "ticketProjectNone": "— none —" },
+    "listSettings": { "untitled": "Untitled", "ticketProjectNone": "— none —", "loadFailed": "Couldn't load list settings: {0}", "ticketProjectsLoadFailed": "Couldn't load ticket projects: {0}" },
     "detailsIsland": { "verifyFailed": "Merge landed, but the list's verify command failed — the task was kept out of Done.", "untrackedCollision": "Merge refused — it would overwrite an untracked file in the target working directory.", "stopOffline": "Worker offline — can't stop the task.", "stopFailed": "Stop failed: {0}", "enqueueFailed": "Queue failed: {0}", "dequeueFailed": "Remove from queue failed: {0}", "resetAndRetryFailed": "Reset & retry failed: {0}", "toggleDoneFailed": "Couldn't update done state: {0}" },
     "mergeSection": { "openWorktreeFailed": "Couldn't open worktree: {0}" },
     "about": { "openPathFailed": "Couldn't open path: {0}" },

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)

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

@@ -34,6 +34,9 @@ public sealed partial class ListSettingsModalViewModel : ViewModelBase
     public Func<string, Task<bool>>? ConfirmAsync { get; set; }
     public Func<string, Task>? ShowErrorAsync { get; set; }
 
+    // Mirrors UsageMonitorModalViewModel.ErrorReported — the caller wires this into FlashFooterError.
+    public event Action<string>? ErrorReported;
+
     [ObservableProperty] private string _name = "";
     [ObservableProperty] private string _workingDir = "";
     [ObservableProperty] private string _defaultCommitType = CommitTypeRegistry.DefaultType;
@@ -65,6 +68,11 @@ public sealed partial class ListSettingsModalViewModel : ViewModelBase
     [NotifyCanExecuteChangedFor(nameof(DeleteCommand))]
     private bool _isLoading;
 
+    // Set when the core load (name/agent/verify command) threw — keeps Save gated even after
+    // IsLoading resets to false in LoadAsync's finally, so a failed load can't clobber the
+    // stored config with blank fields.
+    private bool _loadFailed;
+
     // True once GetTicketProjectsAsync has completed successfully for the current load — Save
     // only writes an explicit TicketProjectId when this is true, so a slow/unreachable ticket
     // system leaves the stored link untouched instead of wiping it to "none".
@@ -128,8 +136,9 @@ public sealed partial class ListSettingsModalViewModel : ViewModelBase
         string? icon = null,
         CancellationToken ct = default)
     {
-        ListConfigDto? cfg;
+        ListConfigDto? cfg = null;
         IsLoading = true;
+        _loadFailed = false;
         try
         {
             ListId = listId;
@@ -147,8 +156,18 @@ public sealed partial class ListSettingsModalViewModel : ViewModelBase
             VerifyCommand = cfg?.VerifyCommand ?? "";
             PowerUseAllowed = cfg?.PowerUseAllowed ?? false;
         }
+        catch (Exception ex)
+        {
+            // BeginLoad fires this without awaiting it — catching here (instead of letting it
+            // propagate) turns what would be an unobserved task exception, with the modal stuck
+            // open and every field blank, into a reported error and a locked Save button.
+            _loadFailed = true;
+            ErrorReported?.Invoke(Loc.T("vm.listSettings.loadFailed", ex.Message));
+        }
         finally { IsLoading = false; }
 
+        if (_loadFailed) return;
+
         // Deliberately NOT awaited: an unreachable ticket system (10s HTTP timeout) must not hold
         // up the rest of the modal. The dropdown just stays empty until this finishes.
         _ = LoadTicketProjectsAsync(cfg?.TicketProjectId);
@@ -179,15 +198,16 @@ public sealed partial class ListSettingsModalViewModel : ViewModelBase
                 : TicketProjects[0];
             _ticketProjectsLoaded = true;
         }
-        catch (Exception)
+        catch (Exception ex)
         {
             // Ticket system unreachable/slow — leave the dropdown as-is. Save's tri-state (below)
             // skips writing TicketProjectId when _ticketProjectsLoaded is false, so the stored
             // link survives instead of being wiped to "none".
+            ErrorReported?.Invoke(Loc.T("vm.listSettings.ticketProjectsLoadFailed", ex.Message));
         }
     }
 
-    private bool CanSave() => !IsLoading;
+    private bool CanSave() => !IsLoading && !_loadFailed;
     private bool CanDelete() => !IsLoading;
 
     [RelayCommand(CanExecute = nameof(CanSave))]

tests/ClaudeDo.Ui.Tests/ViewModels/ListSettingsModalViewModelTests.cs

@@ -38,9 +38,12 @@ public class ListSettingsModalViewModelTests
         public Func<Task<List<TicketProjectDto>>>? TicketProjectsFactory;
         public UpdateListConfigDto? SavedListConfig;
 
+        public Exception? GetListConfigThrows;
+
         public override Task<ListConfigDto?> GetListConfigAsync(string listId)
         {
             GetListConfigCalls++;
+            if (GetListConfigThrows is not null) throw GetListConfigThrows;
             return Task.FromResult(Cfg);
         }
 
@@ -125,4 +128,45 @@ public class ListSettingsModalViewModelTests
 
         Assert.Equal(7, worker.SavedListConfig!.TicketProjectId);
     }
+
+    [Fact]
+    public async Task LoadAsync_CoreLoadThrows_BlocksSaveAndDoesNotOverwriteConfig()
+    {
+        var worker = new CountingWorker
+        {
+            Cfg = new ListConfigDto("opus", null, null),
+            GetListConfigThrows = new InvalidOperationException("worker offline"),
+        };
+        var vm = new ListSettingsModalViewModel(worker, NewFactory());
+        string? reported = null;
+        vm.ErrorReported += m => reported = m;
+
+        await vm.LoadAsync("l1", "List One", "/repo", "feat");
+
+        Assert.False(vm.SaveCommand.CanExecute(null));
+        Assert.NotNull(reported);
+        Assert.Contains("worker offline", reported);
+        Assert.Null(worker.SavedListConfig);
+    }
+
+    [Fact]
+    public async Task LoadAsync_TicketProjectsThrow_ReportsErrorButRestOfLoadStillWorks()
+    {
+        var worker = new CountingWorker
+        {
+            Cfg = new ListConfigDto("opus", null, null, null, null, "make test", null, 7, true),
+            TicketProjectsFactory = () => throw new InvalidOperationException("ticket system down"),
+        };
+        var vm = new ListSettingsModalViewModel(worker, NewFactory());
+        string? reported = null;
+        vm.ErrorReported += m => reported = m;
+
+        await vm.LoadAsync("l1", "List One", "/repo", "feat");
+
+        Assert.Equal("make test", vm.VerifyCommand);
+        Assert.True(vm.PowerUseAllowed);
+        Assert.True(vm.SaveCommand.CanExecute(null));
+        Assert.NotNull(reported);
+        Assert.Contains("ticket system down", reported);
+    }
 }