Pin CultLib abd1a92e: element ids on every list element type, tests follow the new wire and write rules

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

Assets/Scripts/ServerShared/EntitySerializer.cs

@@ -294,4 +294,7 @@ public abstract class EntityPack
 
         return _price;
     }
+
+    // Element identity: minted by the cache on write; "" means unset.
+    [Key(23)] [CultElementId] public string Id = "";
 }