smamanoor79-stack/chirp-mern ? reverse-engineered prompt

Build me a Twitter style social app called Chirp using the MERN stack.

I want people to be able to sign up, log in, and then use a home feed where they can create posts, delete their own posts, upload images, like posts, repost them, and leave comments with emoji support. Users should be able to follow and unfollow each other, view profiles with avatar uploads, and see followers and following in a modal. Make it feel like a real modern social app, with a clean responsive layout, a sticky sidebar on desktop, and a bottom navigation bar on mobile.

Please set it up so the frontend and backend work as separate apps, with the frontend talking to the backend through an API URL environment variable. If you need to, look up current docs online for any setup details.