Add ResultType enum to ReC.Domain.Constants

Introduced a new ResultType enum with values Pre, Main, and Post to represent different result stages. Pre is explicitly set to 1.

src/ReC.Domain/Constants/ResultType.cs

@@ -0,0 +1,8 @@
+namespace ReC.Domain.Constants;
+
+public enum ResultType
+{
+    Pre = 1,
+    Main,
+    Post
+}