surpalsinh22/mern-authentication ? reverse-engineered prompt

Build me a simple MERN authentication app with a clean login and sign up flow.

I want a frontend where a user can create an account, log in, stay logged in after refresh, and log out. After signing in, show a basic protected home page or dashboard with the user’s info and a clear logout button. If the user is not signed in, send them back to the login page. Add good form validation and helpful error messages for things like missing fields, wrong password, or an email that already exists.

On the backend, set up the auth API, user model, password hashing, and session or token based login so the app actually works end to end. Keep the code organized and easy to understand, and make the UI simple but polished enough to feel finished. If anything is unclear, use current docs online and choose sensible defaults.