Team-SyntaxError/canteen_order_system ? reverse-engineered prompt

Build me a simple canteen food ordering system in Python with a MongoDB backend and a clean desktop style interface.

I want three parts, one for customers, one for the canteen admin, and one for a scanner at the counter. Customers should be able to browse items, place an order, see their past orders, and get a QR code after checkout. They should also be able to mark an order as take away. The admin side should let me add and remove menu items, change prices and available quantity, mark certain items as special, and view all orders. The scanner side should scan the QR code, verify that it is real, and show the bill or receipt.

Please make it easy to run after adding the MongoDB connection in a config file, and keep the interface simple and usable. If anything is unclear, look up the current docs online and make sensible choices.