malik-halimeh/OptiCartDH ? reverse-engineered prompt

Build me a simple app called OptiCartDH that lets someone manage a shopping cart experience from start to finish.

I want a clean frontend where users can browse items, add and remove them from a cart, change quantities, and see the total update right away. Make it feel polished and easy to use. If it makes sense, include a basic backend so the data can be saved and shared between the client and server, with a simple way to load the product list and cart state.

Keep it practical and lightweight, and use the existing TypeScript setup in the project. If anything is unclear, make a sensible choice and keep going, and look up current docs online if you need to.