Fix frequency reset to 7115 MHz after start/stop or restart

Save current band and global settings in the STOP path so the next
START restores the frequency the user was on, not the hardcoded default.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

MainForm.pas

@@ -2582,6 +2582,13 @@ begin
     FRXPacketCount := 0;
     FActiveDDC     := 0;
     StatusBar1.Panels[3].Text := 'RX: waiting...';
+    // Сохраняем текущую частоту/настройки чтобы следующий START восстановил их
+    if FDevConnected then
+    begin
+      SaveCurrentBand;
+      FSettings.SaveGlobal(FDevMAC, MakeGlobalSettings);
+      FSettings.Save;
+    end;
     FSpecView.ResetSpectrumBuf;
     FSpecView.DrawSpectrum;
     PbSpectrum.Invalidate;