Server support (stdio) (#19)

* Server support (stdio)
* TestServer project
* Refactored McpClient class to extract shared endpoint logic (with McpServer) to a base class, McpJsonRpcEndpoint.
* Improved xmldoc comments for protocol types, mirroring specification schema comments.
* Update README.MD

src/mcpdotnet/Server/McpServerOptions.cs

@@ -0,0 +1,32 @@
+
+using McpDotNet.Protocol.Types;
+
+namespace McpDotNet.Server;
+
+/// <summary>
+/// Configuration options for the MCP server. This is passed to the client during the initialization sequence, letting it know about the server's capabilities and
+/// protocol version.
+/// <see href="https://spec.modelcontextprotocol.io/specification/2024-11-05/basic/lifecycle/">See the protocol specification for details on capability negotiation</see>
+/// </summary>
+public record McpServerOptions
+{
+    /// <summary>
+    /// Information about this server implementation.
+    /// </summary>
+    public required Implementation ServerInfo { get; init; }
+
+    /// <summary>
+    /// Server capabilities to advertise to the server.
+    /// </summary>
+    public ServerCapabilities? Capabilities { get; init; }
+
+    /// <summary>
+    /// Protocol version to request from the server.
+    /// </summary>
+    public string ProtocolVersion { get; init; } = "2024-11-05";
+
+    /// <summary>
+    /// Timeout for initialization sequence.
+    /// </summary>
+    public TimeSpan InitializationTimeout { get; init; } = TimeSpan.FromSeconds(60);
+}