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/Views/Tabs/PermissionsView.xaml.cs

@@ -0,0 +1,22 @@
+using System.Windows.Controls;
+using Microsoft.Extensions.DependencyInjection;
+using SharepointToolbox.Core.Models;
+using SharepointToolbox.ViewModels.Tabs;
+using SharepointToolbox.Views.Dialogs;
+
+namespace SharepointToolbox.Views.Tabs;
+
+public partial class PermissionsView : UserControl
+{
+    public PermissionsView(IServiceProvider serviceProvider)
+    {
+        InitializeComponent();
+        var vm = serviceProvider.GetRequiredService<PermissionsViewModel>();
+        DataContext = vm;
+        vm.OpenSitePickerDialog = () =>
+        {
+            var factory = serviceProvider.GetRequiredService<Func<TenantProfile, SitePickerDialog>>();
+            return factory(vm.CurrentProfile ?? new TenantProfile());
+        };
+    }
+}