[fix] Add legacy ActionOperatorTypes values for backward compatibility (#255)

Author: paul-fresquet

src/ByteSync.Common/Business/Actions/ActionOperatorTypes.cs

@@ -3,6 +3,13 @@
 public enum ActionOperatorTypes
 {
     // File only
+    
+    // Keep for backward compatibility
+    // Delete when minimal supported version >= 2026.1
+    SynchronizeContentOnly = 1,
+    SynchronizeDate = 2,
+    SynchronizeContentAndDate = 3, 
+    
     CopyContentOnly = 1,
     CopyDatesOnly = 2,
     Copy = 3,