Introduce proper constants

Author: localden

src/ModelContextProtocol.AspNetCore/Auth/McpAuthenticationDefaults.cs

@@ -0,0 +1,17 @@
+namespace ModelContextProtocol.AspNetCore.Auth;
+
+/// <summary>
+/// Default values used by MCP authentication.
+/// </summary>
+public static class McpAuthenticationDefaults
+{
+    /// <summary>
+    /// The default value used for authentication scheme name.
+    /// </summary>
+    public const string AuthenticationScheme = "McpAuth";
+
+    /// <summary>
+    /// The default value used for authentication scheme display name.
+    /// </summary>
+    public const string DisplayName = "MCP Authentication";
+}

src/ModelContextProtocol.AspNetCore/Auth/McpAuthorizationExtensions.cs

@@ -19,7 +19,11 @@ public static AuthenticationBuilder AddMcp(
         this AuthenticationBuilder builder,
         Action<McpAuthenticationOptions>? configureOptions = null)
     {
-        return AddMcp(builder, "McpAuth", "MCP Authentication", configureOptions);
+        return AddMcp(
+            builder, 
+            McpAuthenticationDefaults.AuthenticationScheme, 
+            McpAuthenticationDefaults.DisplayName, 
+            configureOptions);
     }
 
     /// <summary>