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/SitePickerDialog.xaml

@@ -3,6 +3,9 @@
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         Title="Select Sites" Width="600" Height="500"
         WindowStartupLocation="CenterOwner" ShowInTaskbar="False"
+        Background="{DynamicResource AppBgBrush}"
+        Foreground="{DynamicResource TextBrush}"
+        TextOptions.TextFormattingMode="Ideal"
         Loaded="Window_Loaded">
   <Grid Margin="12">
     <Grid.RowDefinitions>
@@ -21,7 +24,7 @@
     <!-- Site list with checkboxes -->
     <ListView x:Name="SiteList" Grid.Row="1" Margin="0,0,0,8"
               SelectionMode="Single"
-              BorderThickness="1" BorderBrush="#CCCCCC">
+              BorderThickness="1" BorderBrush="{DynamicResource BorderSoftBrush}">
       <ListView.View>
         <GridView>
           <GridViewColumn Header="" Width="32">
@@ -40,7 +43,7 @@
 
     <!-- Status text -->
     <TextBlock x:Name="StatusText" Grid.Row="2" Margin="0,0,0,8"
-               Foreground="#555555" FontSize="11" />
+               Foreground="{DynamicResource TextMutedBrush}" FontSize="11" />
 
     <!-- Button row -->
     <DockPanel Grid.Row="3">