Android Login & Shop Integration

I need to add two tightly-connected pieces of functionality to my existing Android application.

First, users must be able to register and sign in with a classic email-and-password flow. The screens are already designed in XML; your task is to wire them up, handle validation, hash/store credentials securely, and keep the user session alive between launches.

Second, once authenticated the user should see live product listings pulled from my online store, drop items into a shopping cart, and track their orders after checkout. I will provide API documentation for the store, but you are free to suggest improvements to the endpoint structure if it simplifies parsing or caching on the mobile side.

Deliverables (all must be present for hand-over)
• Email & password authentication fully implemented and tested
• Product listings rendered with images, price and inventory status
• Add-to-cart flow with item count and total updates in real time
• Order tracking screen that consumes the existing “order status” endpoint
• Clean, commented code in Android Studio project (Kotlin or Java) plus a short README explaining build steps and any third-party libraries used

The upgrade should slot smoothly into the current MVVM codebase; please follow the style already in place and keep dependencies lightweight.