style(ui): polish list sidebar, kbd chips, and session terminal

- Introduce .list-count style for sidebar badges (brighter on active row).
- Bind list header More button to the correct OpenSettingsCommand.
- Give the per-list gear the standard icon-btn look.
- Center-align kbd chip content and title-bar/icon button content.
- Drop the kind-marker column in SessionTerminal and always show the
  scrollbar so the terminal feels like one.

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

@@ -50,23 +50,20 @@
       </Grid>
 
       <!-- ── Log output ── -->
-      <ScrollViewer Name="LogScroll" VerticalScrollBarVisibility="Auto"
+      <ScrollViewer Name="LogScroll"
+                    VerticalScrollBarVisibility="Visible"
+                    AllowAutoHide="False"
                     Padding="10,8,10,12">
         <ItemsControl ItemsSource="{Binding Log}">
           <ItemsControl.ItemTemplate>
             <DataTemplate DataType="vm:LogLineViewModel">
-              <Grid ColumnDefinitions="60,46,*" Margin="0,1">
+              <Grid ColumnDefinitions="60,*" Margin="0,1">
                 <!-- Timestamp -->
                 <TextBlock Grid.Column="0"
                            Classes="log-ts"
                            Text="{Binding TimestampFormatted}"/>
-                <!-- Kind marker -->
-                <TextBlock Grid.Column="1"
-                           Classes="log-kind"
-                           Tag="{Binding ClassName}"
-                           Text="{Binding KindMarker}"/>
                 <!-- Message text — selectable so the user can copy raw output -->
-                <SelectableTextBlock Grid.Column="2"
+                <SelectableTextBlock Grid.Column="1"
                                      Text="{Binding Text}" Tag="{Binding ClassName}"
                                      FontFamily="{DynamicResource MonoFont}" FontSize="11"
                                      Foreground="{DynamicResource TextDimBrush}"