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/ViewModels/Tabs/SearchViewModel.cs

@@ -6,6 +6,7 @@ using CommunityToolkit.Mvvm.Input;
 using Microsoft.Extensions.Logging;
 using Microsoft.Win32;
 using SharepointToolbox.Core.Models;
+using SharepointToolbox.Localization;
 using SharepointToolbox.Services;
 using SharepointToolbox.Services.Export;
 
@@ -79,14 +80,14 @@ public partial class SearchViewModel : FeatureViewModelBase
     {
         if (_currentProfile == null)
         {
-            StatusMessage = "No tenant selected. Please connect to a tenant first.";
+            StatusMessage = TranslationSource.Instance["err.no_tenant_connected"];
             return;
         }
 
         var urls = GlobalSites.Select(s => s.Url).Where(u => !string.IsNullOrWhiteSpace(u)).ToList();
         if (urls.Count == 0)
         {
-            StatusMessage = "Select at least one site from the toolbar.";
+            StatusMessage = TranslationSource.Instance["err.no_sites_selected"];
             return;
         }