feat(03-07): create StorageView XAML, DI registration, and MainWindow wiring

- StorageView.xaml: DataGrid with IndentLevel-based name indentation
- StorageView.xaml.cs: code-behind wiring DataContext to StorageViewModel
- IndentConverter.cs: IndentConverter, BytesConverter, InverseBoolConverter
- App.xaml: register converters and RightAlignStyle as Application.Resources
- App.xaml.cs: register IStorageService, StorageCsvExportService, StorageHtmlExportService, StorageViewModel, StorageView
- MainWindow.xaml: add x:Name=StorageTabItem to Storage TabItem
- MainWindow.xaml.cs: wire StorageTabItem.Content from DI

SharepointToolbox/MainWindow.xaml.cs

@@ -23,6 +23,9 @@ public partial class MainWindow : Window
         // Replace Permissions tab placeholder with the DI-resolved PermissionsView
         PermissionsTabItem.Content = serviceProvider.GetRequiredService<PermissionsView>();
 
+        // Replace Storage tab placeholder with the DI-resolved StorageView
+        StorageTabItem.Content = serviceProvider.GetRequiredService<StorageView>();
+
         // Replace Settings tab placeholder with the DI-resolved SettingsView
         SettingsTabItem.Content = serviceProvider.GetRequiredService<SettingsView>();