AryamanYadav-code/messmate-backend ? reverse-engineered prompt

Build me a working backend for the MessMate app from this repo.

Right now it feels like the project has some starter Expo stuff mixed in with server code, so please clean that up and make the app run properly as a backend service. I want the main server to start without errors, the existing routes and middleware to be wired up correctly, and any database or schema setup scripts to work so I can get the project running locally and deploy it.

If there are missing pieces or the current structure is confusing, please inspect the code, fix the obvious issues, and make the setup simple enough that I can install, run, and test it without digging through the whole repo. If you need to check current docs or best practices online, go ahead.