feat: implement new utility functions

[hashemix]

📌 Summary

Added new utility functions to schema-utils to support MCP application development:

Added and implemented the MCPMessage trait with helpful methods, and provided implementations for ClientMessage and ServerMessage.

Implemented PartialEq, Eq, and Hash traits for requestId, enabling comparison and storage in HashMaps.

💡 Additional Notes

New functions provided by MCPMessage :

• message.is_request() : Returns true if the message is a response type
• message.is_response() : Returns true if the message is a request type
• message.is_notification() : Returns true if the message is a notification type
• message.is_error() : Returns true if the message represents an error
• message.request_id() : Retrieves the request ID associated with the message, if applicable

✨ Changes Made

• Introduced and implemented MCPMessage trait for ClientMessage and ServerMessage
• Implemented PartialEq and Eq and Hash traits for requestId
• Change 3