chore(claude-do): [A3] Settings + Update-Check: OperationStatus für Skill-Inst

Vorgaben: `docs/superpowers/plans/2026-08-11-operation-feedback.md`, Gruppe A, Entwurf A3. P0-1 ist gemergt: `src/ClaudeDo.Ui/Services/OperationStatus.cs` + `src/ClaudeDo.Ui/Views/Controls/OperationIndicator.axaml`.

SCOPE-ÄNDERUNG (Nutzer, 2026-08-12): OnlineInbox Sign-In/Sign-Out ist AUS DEM SCOPE GENOMMEN — vorerst unwichtig. `ViewModels/Modals/Settings/OnlineInboxSettingsViewModel.cs` und die

ClaudeDo-Task: 2356806f-f16e-4652-b615-4562e95c3a65

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

@@ -24,8 +24,14 @@ public class FilesSettingsTabViewModelTests
             throw new Exception(ExceptionMessage);
     }
 
+    private sealed class BlockingWorker : StubWorkerClient
+    {
+        public TaskCompletionSource<SeedResultDto?> Gate { get; } = new();
+        public override Task<SeedResultDto?> RestoreDefaultAgentsAsync() => Gate.Task;
+    }
+
     [Fact]
-    public async Task RestoreDefaultAgents_WhenWorkerThrows_ShowsExceptionMessage_NotGenericOffline()
+    public async Task RestoreDefaultAgents_WhenWorkerThrows_ShowsExceptionMessage_AndResetsOperationState()
     {
         var worker = new ThrowingWorker();
         var vm = new FilesSettingsTabViewModel(worker);
@@ -33,6 +39,25 @@ public class FilesSettingsTabViewModelTests
         await vm.RestoreDefaultAgentsCommand.ExecuteAsync(null);
 
         Assert.Contains(worker.ExceptionMessage, vm.StatusMessage);
-        Assert.False(vm.IsBusy);
+        Assert.False(vm.RestoreOp.IsRunning);
+        Assert.True(vm.RestoreDefaultAgentsCommand.CanExecute(null));
+    }
+
+    [Fact]
+    public async Task RestoreDefaultAgents_WhileRunning_IsRunningTrue_AndCommandLocked()
+    {
+        var worker = new BlockingWorker();
+        var vm = new FilesSettingsTabViewModel(worker);
+
+        var execution = vm.RestoreDefaultAgentsCommand.ExecuteAsync(null);
+
+        Assert.True(vm.RestoreOp.IsRunning);
+        Assert.False(vm.RestoreDefaultAgentsCommand.CanExecute(null));
+
+        worker.Gate.SetResult(new SeedResultDto(1, 0));
+        await execution;
+
+        Assert.False(vm.RestoreOp.IsRunning);
+        Assert.True(vm.RestoreDefaultAgentsCommand.CanExecute(null));
     }
 }