Move the bandmap settings to a Configure Bandmap window

The spot timeouts, the QSY spot and CQ frequency distances and the
recent contact minutes leave the telnet Filters tab for a window under
Config. Each is a numeric box with a range.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

src/Nonemm.App/Windows/EntryWindow.Menu.cs

@@ -572,6 +572,17 @@ public sealed partial class EntryWindow
         }
     }
 
+    private async void OnBandmapSettings(object? sender, RoutedEventArgs e)
+    {
+        BandmapDialog dialog = new(session.Settings);
+        Settings? updated = await dialog.ShowDialog<Settings?>(this);
+        if (updated is not null)
+        {
+            session.Save(updated);
+            Status("bandmap settings saved");
+        }
+    }
+
     private async void OnBroadcastSettings(object? sender, RoutedEventArgs e)
     {
         BroadcastDataDialog dialog = new(session.Settings);