Diagnostics: retry clipboard on COMException to fix crash

windows/PopupWindow.xaml

@@ -282,7 +282,7 @@
                                 Style="{StaticResource SmallButton}" Click="CopyDiag_Click"/>
                     </Grid>
                 </Border>
-                <TextBlock DockPanel.Dock="Top" Text="Email and org IDs are redacted when copied."
+                <TextBlock DockPanel.Dock="Top" Text="Org IDs are redacted when copied."
                            FontSize="10" Foreground="{DynamicResource SecondaryBrush}"
                            Margin="14,6,14,6"/>
                 <ScrollViewer VerticalScrollBarVisibility="Auto">

windows/PopupWindow.xaml.cs

@@ -495,7 +495,12 @@ public partial class PopupWindow : Window
 
     private void CopyDiag_Click(object s, RoutedEventArgs e)
     {
-        Clipboard.SetText(BuildDiagText());
+        var diagText = BuildDiagText();
+        for (int i = 0; i < 5; i++)
+        {
+            try { Clipboard.SetText(diagText); break; }
+            catch (Exception) { System.Threading.Thread.Sleep(100); }
+        }
         CopyDiagButton.Content = "Copied! (IDs redacted)";
         var t = new DispatcherTimer { Interval = TimeSpan.FromSeconds(1.5) };
         t.Tick += (_, _) => { CopyDiagButton.Content = "Copy All"; t.Stop(); };
@@ -624,7 +629,7 @@ public partial class PopupWindow : Window
         sb.AppendLine();
         sb.AppendLine($"Last path: {VM.DiagLastPath}");
         sb.AppendLine($"Last status: {VM.DiagLastStatus}");
-        sb.AppendLine($"Last error: {VM.DiagLastError}");
+        sb.AppendLine($"Last error: {(string.IsNullOrEmpty(VM.DiagLastError) ? "(none)" : VM.DiagLastError)}");
         if (VM.DiagLastFetch.HasValue)
             sb.AppendLine($"Last fetch: {VM.DiagLastFetch.Value:HH:mm:ss}");
         sb.AppendLine();