Refactor pet action management: rename PetAction to PetActionGather, update related models and services, and enhance resource gathering logic.

Models/PetUpdateActionRequest.cs

@@ -2,6 +2,7 @@ namespace pet_companion_api.Models
 {
     public class PetUpdateActionRequest
     {
-        public PetAction PetAction { get; set; }
+        public PetAction? Action { get; set; }
+        public PetActionGather? PetActionGather { get; set; }
     }
 }