Add ping implementation to MCP client

[OrGivati]

According to the spec, the client and server must respond to ping with an empty map.
The server already handles ping requests.
I noticed this behavior is missing when I tested local running FastMCP server against the spring-ai MCP module.
The application failed to load with this error:

Error [ERR_UNHANDLED_ERROR]: Unhandled error. ({
Message received:   error: McpError: MCP error -32601: Method not found: ping

Expected Behavior

MCP Client should respond to ping with empty map

Current Behavior

MCP Client throws method not found execption

Context

If I would like to connect MCP server to my client, the initilization fails over missing ping implementation

See PR #203