Improve how to host McpServer (#30)

src/mcpdotnet/Configuration/DefaultMcpServerBuilder.cs

@@ -0,0 +1,22 @@
+using Microsoft.Extensions.DependencyInjection;
+
+namespace McpDotNet.Configuration;
+
+/// <summary>
+/// Default implementation of <see cref="IMcpServerBuilder"/>.
+/// </summary>
+internal class DefaultMcpServerBuilder : IMcpServerBuilder
+{
+    /// <inheritdoc/>
+    public IServiceCollection Services { get; }
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="DefaultMcpServerBuilder"/> class.
+    /// </summary>
+    /// <param name="services"></param>
+    /// <exception cref="ArgumentNullException"></exception>
+    public DefaultMcpServerBuilder(IServiceCollection services)
+    {
+        Services = services ?? throw new ArgumentNullException(nameof(services));
+    }
+}