refactor(ui): unify text and close button in PlanningDiffView

src/ClaudeDo.Ui/Views/Planning/PlanningDiffView.axaml

@@ -27,11 +27,8 @@
               BorderThickness="0,0,0,1"
               PointerPressed="TitleBar_PointerPressed">
         <Grid ColumnDefinitions="*,Auto" Margin="14,0">
-          <TextBlock Text="Planning — Combined diff"
-                     VerticalAlignment="Center"
-                     FontFamily="{DynamicResource MonoFont}"
-                     FontSize="{StaticResource FontSizeBody}"
-                     Foreground="{DynamicResource TextDimBrush}"/>
+          <TextBlock Classes="title" Text="Planning — Combined diff"
+                     VerticalAlignment="Center"/>
           <Button Grid.Column="1"
                   Classes="icon-btn"
                   Content="✕"
@@ -74,13 +71,9 @@
               <DataTemplate x:DataType="vm:SubtaskDiffRow">
                 <Border Padding="10,8" Background="Transparent">
                   <StackPanel Spacing="2">
-                    <TextBlock Text="{Binding Title}"
-                               FontWeight="SemiBold"
+                    <TextBlock Classes="title" Text="{Binding Title}"
                                TextTrimming="CharacterEllipsis"/>
-                    <TextBlock Text="{Binding DiffStat}"
-                               Opacity="0.7"
-                               FontFamily="{DynamicResource MonoFont}"
-                               FontSize="{StaticResource FontSizeMono}"/>
+                    <TextBlock Classes="meta" Text="{Binding DiffStat}"/>
                   </StackPanel>
                 </Border>
               </DataTemplate>