rudyyyzz/alumni-mern-portal ? reverse-engineered prompt

Build me a MERN alumni portal with a WhatsApp like chat experience for logged in alumni. I want people to be able to see who is online, send messages in real time, know when a message was sent, delivered, and read, and see typing indicators while someone is replying. Add toast notifications and unread message badges when new messages arrive outside the active chat, plus last seen timestamps for offline users. The chat should support images and videos, work well on mobile and desktop, and have a clean dark mode friendly interface with smooth animations. Please use a Node and Express backend with MongoDB for saving messages and users, and a React frontend with real time socket updates. Make sure users can only access chats they belong to, and include basic message validation and login protection. If you need current implementation details, look up the latest docs online as you build it.