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

samples/microsoft.extensions.ai/tools/ToolsConsole/McpAIFunction.cs

@@ -43,7 +43,7 @@ public class McpAIFunction : AIFunction
         // Call the tool through mcpdotnet
         var result = await _client.CallToolAsync(
             _tool.Name,
-            argDict.Count == 0 ? new(): argDict,
+            argDict.Count == 0 ? new() : argDict,
             cancellationToken: cancellationToken
         );