feat(diff): add persisted side-by-side and wrap toggles to the diff viewer

src/ClaudeDo.Ui/Views/Modals/DiffViewerView.axaml

@@ -30,6 +30,12 @@
 
     <DockPanel>
 
+      <!-- View toolbar: layout + wrap, both persisted -->
+      <StackPanel DockPanel.Dock="Top" Orientation="Horizontal" Spacing="8" Margin="16,8,16,0">
+        <ToggleButton Content="{loc:Tr modals.diff.splitView}" IsChecked="{Binding IsSplitView}"/>
+        <ToggleButton Content="{loc:Tr modals.diff.wrapLines}" IsChecked="{Binding WrapLines}"/>
+      </StackPanel>
+
       <!-- Planning toolbar: combined-mode toggle + warning/loading -->
       <StackPanel DockPanel.Dock="Top" Orientation="Horizontal" Spacing="8" Margin="16,8,16,0"
                   IsVisible="{Binding IsPlanning}">
@@ -149,10 +155,10 @@
                            Foreground="{DynamicResource TextMuteBrush}"
                            IsVisible="{Binding SelectedFile.IsEmptyContent}"
                            HorizontalAlignment="Center" VerticalAlignment="Center"/>
-                <ScrollViewer HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Auto"
-                              IsVisible="{Binding SelectedFile.HasLines}">
-                  <ctl:DiffLinesView Lines="{Binding SelectedFile.Lines}"/>
-                </ScrollViewer>
+                <ctl:DiffTextView IsVisible="{Binding SelectedFile.HasLines}"
+                                  File="{Binding SelectedFile}"
+                                  IsSplit="{Binding IsSplitView}"
+                                  WrapLines="{Binding WrapLines}"/>
               </Grid>
             </DockPanel>