sr0707898-hash/my-mern-ecommerce ? reverse-engineered prompt

Build me a simple MERN style ecommerce app that lets people register, browse products, and run the app locally without much setup.

I want a clean Node server with a basic API for user registration and product data, plus a small example config file for environment variables. Keep it straightforward and easy to understand, since I may want to expand it later into a fuller store. If anything is missing, add sensible defaults and make the startup flow clear. Include enough structure so I can plug in a real database and frontend later, but do not overcomplicate it.

If you need to check current best practices or package details, look up the latest docs online. Make sure the app starts cleanly, handles common errors, and is usable right away after adding the env values.