style(ui): tighter sidebar tree rows and shallower child indent

src/ClaudeDo.Ui/Design/IslandStyles.axaml

@@ -866,6 +866,10 @@
     <Setter Property="BorderThickness" Value="1.5" />
     <Setter Property="BorderBrush"     Value="Transparent" />
   </Style>
+  <!-- Folder tree rows sit tighter than the smart lists — a deep tree gets long fast. -->
+  <Style Selector="Border.list-item.tree-row">
+    <Setter Property="Padding" Value="10,4" />
+  </Style>
   <Style Selector="Border.list-item:pointerover">
     <Setter Property="Background" Value="{StaticResource Surface2Brush}" />
   </Style>

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

@@ -19,7 +19,7 @@
                 Background="{DynamicResource MossBrush}" CornerRadius="1"
                 IsVisible="{Binding DropHintAbove}"/>
 
-        <Border Grid.Row="1" Classes="list-item" Classes.active="{Binding IsActive}"
+        <Border Grid.Row="1" Classes="list-item tree-row" Classes.active="{Binding IsActive}"
                 Classes.drop-target="{Binding IsTaskDropTarget}"
                 Tapped="OnItemTapped"
                 DragDrop.AllowDrop="True"
@@ -107,7 +107,7 @@
                 IsVisible="{Binding DropHintAbove}"/>
 
         <StackPanel Grid.Row="1">
-          <Border Classes="list-item"
+          <Border Classes="list-item tree-row"
                   Classes.drop-target="{Binding IsDropTarget}"
                   Tapped="OnFolderTapped"
                   DragDrop.AllowDrop="True"
@@ -148,7 +148,7 @@
           <Panel IsVisible="{Binding !IsCollapsed}">
             <Border Width="1" HorizontalAlignment="Left" Margin="14,0,0,4"
                     Background="{DynamicResource LineBrush}" IsHitTestVisible="False"/>
-            <ItemsControl ItemsSource="{Binding Children}" Margin="20,0,0,0"/>
+            <ItemsControl ItemsSource="{Binding Children}" Margin="12,0,0,0"/>
           </Panel>
         </StackPanel>