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/Core/Models/OperationProgress.cs

@@ -1,7 +1,7 @@
 namespace SharepointToolbox.Core.Models;
 
-public record OperationProgress(int Current, int Total, string Message)
+public record OperationProgress(int Current, int Total, string Message, bool IsIndeterminate = false)
 {
     public static OperationProgress Indeterminate(string message) =>
-        new(0, 0, message);
+        new(0, 0, message, IsIndeterminate: true);
 }