fix(ui): stop the merge-helper tick from re-ticking unticked candidates

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

@@ -41,6 +41,10 @@ public sealed partial class MergeHelperSelectionModalViewModel : ViewModelBase
     // Parent id -> its child rows, built after load; drives the tick-parent-ticks-children cascade.
     private Dictionary<string, List<MergeHelperTaskRowViewModel>> _childrenByParentId = new();
 
+    // Set while ReconcileTickAsync restores remembered ticks, so replaying a parent's state
+    // doesn't cascade over its children's own remembered state.
+    private bool _suppressCascade;
+
     public ObservableCollection<MergeHelperTaskRowViewModel> Tasks { get; } = new();
 
     [ObservableProperty] private string _scopeLabel = "";
@@ -70,16 +74,31 @@ public sealed partial class MergeHelperSelectionModalViewModel : ViewModelBase
         ScopeLabel = Loc.T("modals.mergeHelper.scopeList", listName);
     }
 
-    // LoadAsync rebuilds every row from scratch, which would wipe the user's ticks out from
-    // under them on every tick — capture and restore selection by id around the reload.
+    // LoadAsync rebuilds every row from scratch and re-applies IsTickedByDefault, which would wipe
+    // the user's ticks out from under them on every tick — in BOTH directions. Remembering only
+    // the ticked ids would silently re-tick a row the user deliberately unticked (Idle/Queued/
+    // WaitingForReview/Failed all default to ticked), so carry the full state of every row that
+    // already existed across the reload; only genuinely new rows get the default.
     internal async Task ReconcileTickAsync()
     {
         if (string.IsNullOrEmpty(_listId)) return;
-        var selected = Tasks.Where(t => t.IsSelected).Select(t => t.Id).ToHashSet();
+        var previous = Tasks.ToDictionary(t => t.Id, t => t.IsSelected);
         await LoadAsync();
+
+        // Restore without the parent→children cascade: it would overwrite a child's own remembered
+        // state with its parent's, undoing exactly the per-child choice being restored.
+        _suppressCascade = true;
+        try
+        {
             foreach (var t in Tasks)
-            if (selected.Contains(t.Id))
-                t.IsSelected = true;
+                if (previous.TryGetValue(t.Id, out var wasSelected))
+                    t.IsSelected = wasSelected;
+        }
+        finally
+        {
+            _suppressCascade = false;
+        }
+
         OnPropertyChanged(nameof(CanConfirm));
     }
 
@@ -162,7 +181,8 @@ public sealed partial class MergeHelperSelectionModalViewModel : ViewModelBase
         // Ticking/unticking a parent cascades to its children; a child can still be
         // deselected on its own afterwards without affecting the parent's checkbox —
         // ClaudeDo has no indeterminate/tri-state parent checkbox.
-        if (sender is MergeHelperTaskRowViewModel row
+        if (!_suppressCascade
+            && sender is MergeHelperTaskRowViewModel row
             && _childrenByParentId.TryGetValue(row.Id, out var children))
         {
             foreach (var child in children) child.IsSelected = row.IsSelected;

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

@@ -89,6 +89,73 @@ public class MergeHelperSelectionModalViewModelTests : IDisposable
         Assert.False(vm.Tasks.Single(t => t.Id == "t-children").IsSelected);
     }
 
+    [Fact]
+    public async Task ReconcileTick_KeepsBothTicksAndUnticks_AndDefaultsOnlyNewRows()
+    {
+        await SeedAllStatusesAsync();
+        var vm = BuildVm();
+        vm.Configure("L1", "Work");
+        await vm.LoadAsync();
+
+        // The user's own choices, both directions, against the defaults.
+        vm.Tasks.Single(t => t.Id == "t-idle").IsSelected = false;      // default true -> off
+        vm.Tasks.Single(t => t.Id == "t-running").IsSelected = true;    // default false -> on
+
+        await using (var db = NewContext())
+        {
+            db.Tasks.Add(new TaskEntity
+            {
+                Id = "t-new", ListId = "L1", Title = "arrived later",
+                Status = TaskStatus.Idle, CreatedAt = DateTime.UtcNow, SortOrder = 99,
+            });
+            await db.SaveChangesAsync();
+        }
+
+        await vm.ReconcileTickAsync();
+
+        Assert.False(vm.Tasks.Single(t => t.Id == "t-idle").IsSelected);
+        Assert.True(vm.Tasks.Single(t => t.Id == "t-running").IsSelected);
+        Assert.True(vm.Tasks.Single(t => t.Id == "t-queued").IsSelected);   // untouched, keeps default
+        Assert.True(vm.Tasks.Single(t => t.Id == "t-new").IsSelected);      // new row gets the default
+    }
+
+    [Fact]
+    public async Task ReconcileTick_DoesNotCascadeParentStateOverAnUntickedChild()
+    {
+        await using (var db = NewContext())
+        {
+            db.Lists.Add(new ListEntity { Id = "L1", Name = "Work", CreatedAt = DateTime.UtcNow });
+            db.Tasks.Add(new TaskEntity
+            {
+                Id = "parent", ListId = "L1", Title = "parent",
+                Status = TaskStatus.Idle, CreatedAt = DateTime.UtcNow, SortOrder = 0,
+            });
+            db.Tasks.Add(new TaskEntity
+            {
+                Id = "child1", ListId = "L1", Title = "child1", ParentTaskId = "parent",
+                Status = TaskStatus.Idle, CreatedAt = DateTime.UtcNow, SortOrder = 1,
+            });
+            db.Tasks.Add(new TaskEntity
+            {
+                Id = "child2", ListId = "L1", Title = "child2", ParentTaskId = "parent",
+                Status = TaskStatus.Idle, CreatedAt = DateTime.UtcNow, SortOrder = 2,
+            });
+            await db.SaveChangesAsync();
+        }
+
+        var vm = BuildVm();
+        vm.Configure("L1", "Work");
+        await vm.LoadAsync();
+
+        vm.Tasks.Single(t => t.Id == "child1").IsSelected = false;   // parent stays ticked
+
+        await vm.ReconcileTickAsync();
+
+        Assert.True(vm.Tasks.Single(t => t.Id == "parent").IsSelected);
+        Assert.False(vm.Tasks.Single(t => t.Id == "child1").IsSelected);
+        Assert.True(vm.Tasks.Single(t => t.Id == "child2").IsSelected);
+    }
+
     [Fact]
     public async Task Load_PerListScope_FiltersToThatList()
     {