Gaini-Laxman/nexamart-fresh-be ? reverse-engineered prompt

Build me the backend for Nexamart Fresh as a clean Java API that I can grow into a real app.

I want a solid starting point with the usual stuff a backend needs, like user signup and login, basic security, and CRUD endpoints for products and other store data. Please set it up so it can talk to a database, handle errors nicely, and return clear JSON responses. Make it easy to run locally and easy to extend later, with sensible structure and a few example endpoints or seed data so I can test it right away.

If you need to look up current docs or best practices for the Java stack, go ahead and do that. Keep the code tidy, include anything needed to get it running, and make sure it feels like a real production ready starting point rather than a toy project.