nilezt/BLE-Indoor-Positioning ? reverse-engineered prompt

Build me an Android project for indoor positioning using Bluetooth beacons.

I want a reusable Java library that can take scan results from nearby BLE beacons, keep track of recent advertising packets, estimate distance from RSSI, and calculate the device’s current location from multiple beacons. Please include a simple demo app that shows the live beacon data and the estimated position on screen so I can see it working.

It should be easy to plug in my own Bluetooth scanning code, and it should expose simple callbacks when beacons update and when the location changes. If you need to check any current Android or Bluetooth docs while wiring it up, go ahead and look them up online.

Please make the project buildable, clean, and ready to run, with the core logic separated from the demo app.