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/Islands/SessionTerminalView.axaml

@@ -51,11 +51,12 @@
       </Grid>
 
       <!-- ── Log output ── -->
+      <!-- Inset on the content, not on the ScrollViewer — Avalonia 12 excludes
+           ScrollViewer.Padding from the Extent, which clips the last log lines. -->
       <ScrollViewer Name="LogScroll"
                     VerticalScrollBarVisibility="Visible"
-                    AllowAutoHide="False"
-                    Padding="10,8,10,12">
-        <ItemsControl ItemsSource="{Binding #Root.Entries}">
+                    AllowAutoHide="False">
+        <ItemsControl ItemsSource="{Binding #Root.Entries}" Margin="10,8,10,12">
           <ItemsControl.ItemTemplate>
             <DataTemplate DataType="vm:LogLineViewModel">
               <Grid ColumnDefinitions="60,*" Margin="0,1">