fix(07): fix people picker selection and audit service authentication

People picker ListBox used MouseBinding which fires before SelectedItem
updates, causing null CommandParameter. Replaced with SelectionChanged
event handler in code-behind.

AuditUsersAsync created TenantProfile with empty ClientId, causing
ArgumentException in SessionManager. Added currentProfile parameter
to pass the authenticated tenant's ClientId through.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

SharepointToolbox/Views/Tabs/UserAccessAuditView.xaml.cs

@@ -1,4 +1,5 @@
 using System.Windows.Controls;
+using SharepointToolbox.Services;
 using SharepointToolbox.ViewModels.Tabs;
 
 namespace SharepointToolbox.Views.Tabs;
@@ -10,4 +11,17 @@ public partial class UserAccessAuditView : UserControl
         InitializeComponent();
         DataContext = viewModel;
     }
+
+    private void SearchResultsListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
+    {
+        if (sender is ListBox listBox && listBox.SelectedItem is GraphUserResult user)
+        {
+            var vm = (UserAccessAuditViewModel)DataContext;
+            if (vm.AddUserCommand.CanExecute(user))
+                vm.AddUserCommand.Execute(user);
+
+            // Clear selection so the same item can be re-selected if needed
+            listBox.SelectedItem = null;
+        }
+    }
 }