ROHAN-8504/ECOM-BACKEND-sab- ? reverse-engineered prompt

Build me a backend for a simple ecommerce store. I want a clean API that can handle user signup and login, manage products, let users add items to a cart, place orders, and keep basic admin access for creating, updating, and deleting products. Set it up with a clear structure so controllers, routes, models, and middleware are organized and easy to follow.

Please include sensible validation, error handling, and protected routes where needed. Use whatever database setup fits best for a small ecommerce app, and make sure the server starts cleanly and the API is easy to test with tools like Postman. If you need to check current library docs or best practices while building it, go ahead and look them up online. I mainly want a solid working backend that feels like a real ecommerce API and is easy to extend later.