io.modelcontextprotocol.client.transport.StdioClientTransport#closeGracefully

從 io.modelcontextprotocol.client.transport.StdioClientTransport#closeGracefully 開始，並重現 issue 中的 Windows npx.cmd 範例。調查啟動的程序及其子程序是如何被終止的；完成的標準是關閉 client 後，子程序樹也會結束，且 main 方法可以正常返回。

Bug description
When npx is launched on Windows, a related subprocess is initiated. When using the io.modelcontextprotocol.client.transport.StdioClientTransport#closeGracefully method to close, this.process.destroy() will only terminate the current process, but the subprocess cannot be closed, resulting in the main method not being able to end normally. Therefore, the taskkill pid /F /T command needs to be used to terminate it.

Environment
jdk 17
mcp 0.12.0-SNAPSHOT
windows 11
Steps to reproduce
StdioClientTransport stdioClientTransport = new StdioClientTransport(ServerParameters.builder("D:\dev\nodejs\npx.cmd").args(Arrays.asList("-y","@wopal/mcp-server-hotnews")).build());
McpSyncClient mcpClient = McpClient.sync(stdioClientTransport)
.requestTimeout(Duration.ofSeconds(20L))
.capabilities(McpSchema.ClientCapabilities.builder()
.roots(true)
.sampling()
.build())
.build();
mcpClient.initialize();
McpSchema.ListToolsResult listToolsResult = mcpClient.listTools();
List<McpSchema.Tool> tools = listToolsResult.tools();
System.out.println(tools.get(0).name());
mcpClient.closeGracefully();

Expected behavior
Close the child processes simultaneously

Minimal Complete Reproducible example
StdioClientTransport stdioClientTransport = new StdioClientTransport(ServerParameters.builder("D:\dev\nodejs\npx.cmd").args(Arrays.asList("-y","@wopal/mcp-server-hotnews")).build());
McpSyncClient mcpClient = McpClient.sync(stdioClientTransport)
.requestTimeout(Duration.ofSeconds(20L))
.capabilities(McpSchema.ClientCapabilities.builder()
.roots(true)
.sampling()
.build())
.build();
mcpClient.initialize();
McpSchema.ListToolsResult listToolsResult = mcpClient.listTools();
List<McpSchema.Tool> tools = listToolsResult.tools();
System.out.println(tools.get(0).name());
mcpClient.closeGracefully();