imammuhtadi/avatar_pos — reverse-engineered prompt

Build me a modern point of sale app called Avatar POS for a small shop. I want it to work on web, desktop, Android, and iPhone from the same Flutter codebase.

The app should let staff sign in, manage products and categories, add items to a cart, change quantities, take a payment, and save each sale as a transaction. It should automatically reduce stock after checkout and let me see past transactions. Please include a clean dashboard style interface that works well on phones and bigger screens, with light and dark mode.

Use Supabase for login, database, stock, products, and transactions. Add a simple setup using environment variables so I can connect my own Supabase project. Keep the code organized by feature so it’s easy to maintain. If you need current Flutter or Supabase details, look them up online.