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/App.xaml.cs

@@ -88,6 +88,13 @@ public partial class App : Application
         services.AddTransient<ProfileManagementDialog>();
         services.AddTransient<SettingsView>();
 
+        // Phase 3: Storage
+        services.AddTransient<IStorageService, StorageService>();
+        services.AddTransient<StorageCsvExportService>();
+        services.AddTransient<StorageHtmlExportService>();
+        services.AddTransient<StorageViewModel>();
+        services.AddTransient<StorageView>();
+
         // Phase 2: Permissions
         services.AddTransient<IPermissionsService, PermissionsService>();
         services.AddTransient<ISiteListService, SiteListService>();