chore: release v2.4

- Add theme system (Dark/Light palettes, ModernTheme, ThemeManager)
- Add InputDialog, Spinner common view
- Add DuplicatesCsvExportService
- Refresh views, dialogs, and view models across tabs
- Update localization strings (en/fr)
- Tweak services (transfer, permissions, search, user access, ownership elevation, bulk operations)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

SharepointToolbox/Views/Tabs/BulkMembersView.xaml

@@ -1,10 +1,13 @@
 <UserControl x:Class="SharepointToolbox.Views.Tabs.BulkMembersView"
              xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-             xmlns:loc="clr-namespace:SharepointToolbox.Localization">
+             xmlns:loc="clr-namespace:SharepointToolbox.Localization"
+             xmlns:common="clr-namespace:SharepointToolbox.Views.Common">
     <DockPanel Margin="10">
         <!-- Options Panel (Left) -->
-        <StackPanel DockPanel.Dock="Left" Width="240" Margin="0,0,10,0">
+        <ScrollViewer DockPanel.Dock="Left" Width="240" Margin="0,0,10,0"
+                      VerticalScrollBarVisibility="Auto" HorizontalScrollBarVisibility="Disabled">
+        <StackPanel>
             <Button Content="{Binding Source={x:Static loc:TranslationSource.Instance}, Path=[bulkmembers.import]}"
                     Command="{Binding ImportCsvCommand}" Margin="0,0,0,5" />
             <Button Content="{Binding Source={x:Static loc:TranslationSource.Instance}, Path=[bulkmembers.example]}"
@@ -19,8 +22,8 @@
                     Command="{Binding CancelCommand}"
                     Visibility="{Binding IsRunning, Converter={StaticResource BoolToVisibilityConverter}}" />
 
-            <ProgressBar Height="20" Margin="0,10,0,5" Value="{Binding ProgressValue}"
-                         Visibility="{Binding IsRunning, Converter={StaticResource BoolToVisibilityConverter}}" />
+            <common:Spinner Width="20" Height="20" HorizontalAlignment="Left" Margin="0,10,0,5"
+                            Visibility="{Binding IsRunning, Converter={StaticResource BoolToVisibilityConverter}}" />
             <TextBlock Text="{Binding StatusMessage}" TextWrapping="Wrap" />
 
             <TextBlock Text="{Binding ResultSummary}" FontWeight="Bold" Margin="0,10,0,5" />
@@ -29,6 +32,7 @@
             <Button Content="{Binding Source={x:Static loc:TranslationSource.Instance}, Path=[bulk.exportfailed]}"
                     Command="{Binding ExportFailedCommand}" />
         </StackPanel>
+        </ScrollViewer>
 
         <!-- Preview DataGrid (Right) -->
         <DataGrid ItemsSource="{Binding PreviewRows}" AutoGenerateColumns="False"