sunil5058/simple-mern-todo ? reverse-engineered prompt

Please finish this simple todo app so I can run the whole thing with Docker from a fresh clone.

It already has a small React frontend and an Express backend that talks to MongoDB, and I want the app to work locally and inside containers the same way. Add whatever is missing so the backend runs on port 5000, the frontend builds and serves on port 5173, and the frontend can call the backend correctly in Docker. Set it up so the backend can reach MongoDB by service name, and make sure the todos stay saved even after restarting the containers.

If you need to, look up the current docs for the best way to wire this up. I’d like one simple command to start everything, something like docker compose up --build, and then I should be able to open the app in the browser and use the todo list normally.