sujan24-w/auth-mern ? reverse-engineered prompt

Build me a simple full stack login and signup app where people can create an account, sign in, and then see a private home page only after they are authenticated.

I want a clean, modern UI on the frontend, with forms for register and login, basic validation, and a clear success or error message when something goes wrong. After login, the user should stay signed in when possible, and there should be an easy logout button. Please make the app feel polished enough to deploy and use right away.

On the backend, set up the user auth flow, store user accounts safely, and protect private routes so only logged in users can access them. If you need to check current docs or best practices while building it, go ahead and look them up.

Make the whole thing work end to end and keep the code organized so it is easy to run locally and deploy.