feat(ui): mark agent-suggested improvement children in the task tree

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/ClaudeDo.Ui/Design/IslandStyles.axaml

@@ -88,6 +88,9 @@
     <!-- Icon.Warning — filled triangle with exclamation (roadblock badge) -->
     <StreamGeometry x:Key="Icon.Warning">F0 M12 3 L22 20 H2 Z M11 9 H13 V14 H11 Z M11 16 H13 V18 H11 Z</StreamGeometry>
 
+    <!-- Icon.AgentSuggested — filled diamond (agent-suggested child badge) -->
+    <StreamGeometry x:Key="Icon.AgentSuggested">M12 3 L20 12 L12 21 L4 12 Z</StreamGeometry>
+
     <!-- Icon.Settings (gear) -->
     <StreamGeometry x:Key="Icon.Settings">M12 8a4 4 0 1 0 0 8 4 4 0 0 0 0-8z M19.43 12.98c.04-.32.07-.64.07-.98s-.03-.66-.07-.98l2.11-1.65a.5.5 0 0 0 .12-.64l-2-3.46a.5.5 0 0 0-.61-.22l-2.49 1a7.03 7.03 0 0 0-1.69-.98l-.38-2.65a.5.5 0 0 0-.5-.42h-4a.5.5 0 0 0-.5.42l-.38 2.65c-.61.25-1.17.59-1.69.98l-2.49-1a.5.5 0 0 0-.61.22l-2 3.46a.5.5 0 0 0 .12.64l2.11 1.65c-.04.32-.07.65-.07.98s.03.66.07.98l-2.11 1.65a.5.5 0 0 0-.12.64l2 3.46a.5.5 0 0 0 .61.22l2.49-1c.52.4 1.08.73 1.69.98l.38 2.65a.5.5 0 0 0 .5.42h4a.5.5 0 0 0 .5-.42l.38-2.65c.61-.25 1.17-.59 1.69-.98l2.49 1a.5.5 0 0 0 .61-.22l2-3.46a.5.5 0 0 0-.12-.64l-2.11-1.65z</StreamGeometry>
 

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

@@ -24,6 +24,7 @@ public sealed partial class TaskRowViewModel : ViewModelBase
     [ObservableProperty] private bool _dropHintAbove;
     [ObservableProperty] private bool _dropHintBelow;
     [ObservableProperty] private string? _parentTaskId;
+    [ObservableProperty] private string? _createdBy;
     [ObservableProperty] private string? _blockedByTaskId;
     [ObservableProperty] private bool _isExpanded = true;
     [ObservableProperty] private bool _hasPlanningChildren;
@@ -38,7 +39,8 @@ public sealed partial class TaskRowViewModel : ViewModelBase
     public int StepsCount { get; init; }
     public int StepsCompleted { get; init; }
 
-    public bool IsChild          => !string.IsNullOrEmpty(ParentTaskId);
+    public bool IsChild            => !string.IsNullOrEmpty(ParentTaskId);
+    public bool IsAgentSuggested   => IsChild && !string.IsNullOrEmpty(CreatedBy) && CreatedBy == ParentTaskId;
     public bool IsPlanningParent => PlanningPhase != PlanningPhase.None
                                   || HasPlanningChildren;
     // A subtask is Draft until its planning parent is finalized, then Planned (queueable).
@@ -128,12 +130,15 @@ public sealed partial class TaskRowViewModel : ViewModelBase
     partial void OnParentTaskIdChanged(string? value)
     {
         OnPropertyChanged(nameof(IsChild));
+        OnPropertyChanged(nameof(IsAgentSuggested));
         OnPropertyChanged(nameof(IsDraft));
         OnPropertyChanged(nameof(IsPlanned));
         OnPropertyChanged(nameof(CanSendToQueue));
         OnPropertyChanged(nameof(CanOpenPlanningSession));
     }
 
+    partial void OnCreatedByChanged(string? value) => OnPropertyChanged(nameof(IsAgentSuggested));
+
     partial void OnParentFinalizedChanged(bool value)
     {
         OnPropertyChanged(nameof(IsDraft));
@@ -214,6 +219,7 @@ public sealed partial class TaskRowViewModel : ViewModelBase
         DiffAdditions     = add;
         DiffDeletions     = del;
         ParentTaskId      = t.ParentTaskId;
+        CreatedBy         = t.CreatedBy;
         BlockedByTaskId   = t.BlockedByTaskId;
         RoadblockCount    = t.RoadblockCount;
     }

src/ClaudeDo.Ui/Views/Islands/TaskRowView.axaml

@@ -136,6 +136,13 @@
                       IsVisible="{Binding HasRoadblock}"
                       ToolTip.Tip="{Binding RoadblockTooltip}"/>
 
+            <!-- Agent-suggested badge -->
+            <PathIcon Width="10" Height="10" VerticalAlignment="Center"
+                      Data="{StaticResource Icon.AgentSuggested}"
+                      Foreground="#5C8FA8"
+                      IsVisible="{Binding IsAgentSuggested}"
+                      ToolTip.Tip="Suggested by the agent"/>
+
             <!-- Status chip -->
             <Border Classes="chip"
                     Classes.running="{Binding Status, Converter={StaticResource EqStatus}, ConverterParameter=Running}"