- added function to mark a channel for swapping + swap with current channel

- replaced misuse of "FileLoadException" with a custom LoaderException to handle file loading issues with better continue/fail logic
- removed "Save As" and replaced it with "Convert list" menu item that shows information on how to use a reference list instead of direct conversion

source/ChanSort.Loader.Enigma2/Serializer.cs

@@ -40,7 +40,6 @@ namespace ChanSort.Loader.Enigma2
       this.Features.CanHideChannels = false;
       this.Features.FavoritesMode = FavoritesMode.MixedSource;
       this.Features.MaxFavoriteLists = 0; // dynamically added
-      this.Features.CanSaveAs = false;
 
       this.channels.IsMixedSourceFavoritesList = true;
       this.DataRoot.AddChannelList(this.channels);