Add MethodReturnTypeNameAttribute class

Introduces the `MethodReturnTypeNameAttribute` class in the
`BlazorExpress.Core` namespace. This attribute allows for the
specification of a method's return type name through a constructor
that accepts a string parameter, which is stored in a read-only
property called `TypeName`.

NOTE: This commit message is auto-generated using GitHub Copilot.

Author: gvreddy04

BlazorExpress.Core/Attributes/MethodReturnTypeNameAttribute.cs

@@ -0,0 +1,22 @@
+namespace BlazorExpress.Core;
+
+/// <summary>
+/// Attribute to specify the method return type name.
+/// </summary>
+public class MethodReturnTypeNameAttribute : Attribute
+{
+    #region Constructors
+    
+    public MethodReturnTypeNameAttribute(string typeName)
+    {
+        TypeName = typeName;
+    }
+
+    #endregion
+
+    #region Properties, Indexers
+
+    public string TypeName { get; }
+
+    #endregion
+}