Anirudh-Negii/quickcart ? reverse-engineered prompt

Build me a full stack e commerce app called QuickCart with a clean responsive storefront and a simple admin style product area. Users should be able to sign up, log in, stay signed in with secure token based auth, view their profile, browse all products, open a product detail page, and add, edit, or delete products when logged in. I also want product image uploads working through ImageKit, plus form checks and friendly validation messages if something is missing or wrong. Please include a custom 404 page, loading states, toast style feedback, and a smooth mobile friendly layout. Use a React frontend and a Node, Express, MongoDB backend, and wire the frontend to the API with proper login and refresh token handling. If you need to look up current docs online for anything, go ahead and do that.