Set ApiKeyLocation enum underlying type to byte

Changed ApiKeyLocation enum to use byte as its underlying type instead of the default int, reducing memory usage and improving clarity for serialization scenarios.

src/ReC.Domain/Constants/ApiKeyLocation.cs

@@ -1,6 +1,6 @@
 namespace ReC.Domain.Constants;
 
-public enum ApiKeyLocation
+public enum ApiKeyLocation : byte
 {
     Header = 0,
     Query = 1