fix(ui): stop clipping the last log line in scrollable output

Avalonia 12 leaves ScrollViewer.Padding out of the scroll Extent, so at
maximum offset the content still overhangs the viewport by the padding
height — the last lines were cut off and unreachable even after
ScrollToEnd(). Move the inset onto the content (Margin on the inner
ItemsControl/StackPanel) and leave the ScrollViewer padding-free.

Affects the work console Output/Git/Session tabs, the reusable session
terminal (task + prep log) and the log visualizer.

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

@@ -42,8 +42,8 @@
 
       <!-- Last 30 min, newest-first -->
       <Border Classes="terminal" Margin="14,0,14,14">
-        <ScrollViewer VerticalScrollBarVisibility="Visible" AllowAutoHide="False" Padding="10,8">
-          <ItemsControl ItemsSource="{Binding Rows}">
+        <ScrollViewer VerticalScrollBarVisibility="Visible" AllowAutoHide="False">
+          <ItemsControl ItemsSource="{Binding Rows}" Margin="10,8">
             <ItemsControl.ItemTemplate>
               <DataTemplate DataType="vm:LogVisualizerRow">
                 <Grid ColumnDefinitions="64,*" Margin="0,1">