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/InputDialog.xaml.cs

@@ -0,0 +1,28 @@
+using System.Windows;
+
+namespace SharepointToolbox.Views.Dialogs;
+
+public partial class InputDialog : Window
+{
+    public string ResponseText => ResponseBox.Text;
+
+    public InputDialog(string prompt, string initialValue)
+    {
+        InitializeComponent();
+        PromptText.Text = prompt;
+        ResponseBox.Text = initialValue ?? string.Empty;
+        Loaded += (_, _) => { ResponseBox.Focus(); ResponseBox.SelectAll(); };
+    }
+
+    private void Ok_Click(object sender, RoutedEventArgs e)
+    {
+        DialogResult = true;
+        Close();
+    }
+
+    private void Cancel_Click(object sender, RoutedEventArgs e)
+    {
+        DialogResult = false;
+        Close();
+    }
+}