feat(02-07): create PermissionsView XAML + code-behind and register DI

- Created PermissionsView.xaml with left scan-config panel and right results DataGrid
- Created PermissionsView.xaml.cs wiring ViewModel via IServiceProvider, factory for SitePickerDialog
- Updated App.xaml.cs: registered IPermissionsService, ISiteListService, CsvExportService,
  HtmlExportService, PermissionsViewModel, PermissionsView, SitePickerDialog, and
  Func<TenantProfile, SitePickerDialog> factory; also registered ISessionManager -> SessionManager
- Updated MainWindow.xaml: replaced FeatureTabBase stub with named PermissionsTabItem
- Updated MainWindow.xaml.cs: wires PermissionsTabItem.Content from DI-resolved PermissionsView
- Added CurrentProfile public accessor, SitesSelectedLabel computed property, and
  IsMaxDepth toggle property to PermissionsViewModel
- Build: 0 errors, 0 warnings. Tests: 60 passed, 3 skipped (live/interactive)

SharepointToolbox/MainWindow.xaml.cs

@@ -20,6 +20,9 @@ public partial class MainWindow : Window
         // Wire profile management dialog factory
         viewModel.OpenProfileManagementDialog = () => serviceProvider.GetRequiredService<ProfileManagementDialog>();
 
+        // Replace Permissions tab placeholder with the DI-resolved PermissionsView
+        PermissionsTabItem.Content = serviceProvider.GetRequiredService<PermissionsView>();
+
         // Replace Settings tab placeholder with the DI-resolved SettingsView
         SettingsTabItem.Content = serviceProvider.GetRequiredService<SettingsView>();