[enhancement] add struct support for NewToolResponse

[DURUII]

func(args WeatherArgs) (*mcp.ToolResponse, error) {
	return mcp.NewToolResponse(mcp.NewTextContent(
		fmt.Sprintf("%v", WeatherData{
			Temperature: 75.5,
			Conditions:  "sunny",
			Location:    args.Location,
		}),
	)), nil
})

this might not be that elegant, why should I use a fmt.Sprintf to build a response, while in python, it goes like:

@mcp.tool()
def get_weather(location: str) -> dict:
    """Gets current weather for a location."""
    # This would normally call a weather API
    # Simplified for demonstration
    return {
        "temperature": 72.5,
        "conditions": "Sunny",
        "location": location
    }