Mark the CQ frequency on the bandmap and leave Run when the radio moves off it

Starting Run stores the frequency in the position. The bandmap draws a
purple, bold "CQ Frequency" pseudospot there, which is not added to the
shared bandmap, and a click on it tunes back and sets Run. A move of more
than 3 kHz (a setting on the telnet Filters tab) while running switches
to search and pounce.

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

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

@@ -462,7 +462,7 @@ public sealed partial class EntryWindow
 
     private void OnShowCheck(object? sender, RoutedEventArgs e) => Show(() => new CheckWindow(session));
 
-    private void OnShowBandmap(object? sender, RoutedEventArgs e) => Show(() => new BandmapWindow(session, Tune));
+    private void OnShowBandmap(object? sender, RoutedEventArgs e) => Show(() => new BandmapWindow(session, Tune, ReturnToCq));
 
     private void OnShowAvailable(object? sender, RoutedEventArgs e) =>
         Show(() => new AvailableWindow(session, Tune));
@@ -712,6 +712,14 @@ public sealed partial class EntryWindow
         }
     }
 
+    /// A click on the CQ frequency on the bandmap: back to where the CQs went
+    /// out, and running again.
+    private void ReturnToCq(Frequency frequency)
+    {
+        Tune(frequency, "");
+        SetRunning(true);
+    }
+
     private void Tune(Frequency frequency, string call)
     {
         if (Logging is null)