mfbgull/minierp-flutter ? reverse-engineered prompt

Build me a desktop ERP app for small and medium businesses that runs on Windows, macOS, and Linux. I want one place to manage inventory, purchasing, sales, production, payments, and financial reports, with a simple business friendly interface that does not feel like a giant enterprise system.

It should have a Flutter desktop app for the main screens, and a backend server with a SQLite database that handles the data and starts up cleanly. On Linux, I want the easiest possible install where the app can bundle everything and launch the server automatically. On the other platforms, it can connect to a separate server running locally.

Please make it usable out of the box with a default admin login, automatic database setup on first run, and sensible configuration for the server address. If you need to check current Flutter or Node setup details, look them up online.