Develop a real-time online chat system using Next.js, incorporating a server component for handling messages and user sessions. Implement session storage to persist messages, ensuring they are retained until the user's session ends. Design the chat system with a focus on user experience, incorporating a modern and intuitive UI that aligns with Vercel's design principles. Include a feature that allows users to join the chat via a unique, secure link containing a security key for authentication. The system should prioritize security, ensuring that only authorized users with the correct key can access the chat. The UI should be responsive and accessible, providing a seamless experience across different devices. Consider integrating an AI model to enhance the chat functionality, such as for message suggestions or sentiment analysis. The system should be optimized for performance and scalability, reflecting Vercel's commitment to providing a fast and reliable platform. Ensure the chat system is fully functional, including all necessary components for message sending, receiving, and user management. The system should also include error handling and provide informative feedback to the user in case of any issues. The chat system should be deployable on Vercel, and the code should be optimized for Vercel's environment.