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/Dialogs/ConfirmBulkOperationDialog.xaml

@@ -4,6 +4,9 @@
         xmlns:loc="clr-namespace:SharepointToolbox.Localization"
         Title="{Binding Source={x:Static loc:TranslationSource.Instance}, Path=[bulk.confirm.title]}"
         Width="450" Height="220" WindowStartupLocation="CenterOwner"
+        Background="{DynamicResource AppBgBrush}"
+        Foreground="{DynamicResource TextBrush}"
+        TextOptions.TextFormattingMode="Ideal"
         ResizeMode="NoResize">
     <Grid Margin="20">
         <Grid.RowDefinitions>