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/AppSession.cs

@@ -313,7 +313,7 @@ public sealed partial class AppSession : IDisposable
         positions.Clear();
         for (int number = 1; number <= PositionCount; number++)
         {
-            positions.Add(new OperatingPosition(Logging, number));
+            positions.Add(new OperatingPosition(Logging, number) { CqLeaveHertz = Settings.CqLeaveHertz });
         }
         activeRadio = Math.Min(activeRadio, positions.Count - 1);
         // the other stations refuse to resynchronise with a station on another
@@ -995,6 +995,10 @@ public sealed partial class AppSession : IDisposable
     {
         spotFilter = Settings.SpotFilter.ToFilter(BandPlan, Settings.Station, Countries, Calls, History);
         Bandmap.Lifetime = TimeSpan.FromMinutes(Math.Max(1, Settings.SpotTimeoutMinutes));
+        foreach (OperatingPosition position in positions)
+        {
+            position.CqLeaveHertz = Settings.CqLeaveHertz;
+        }
     }
 
     public void ReloadSupportFiles()