hnsvrdmn/flipper-rfid-metal-detector — reverse-engineered prompt

Build me a Flipper Zero app that uses the 125 kHz RFID antenna like a simple metal detector. I know it won’t be a real detector, just an experimental tool that reacts when metal is a few centimeters away.

The app should keep the RFID field active, watch for changes in the signal, and show a clear bar graph on the screen when something is detected. I want it to also give feedback with sound, vibration, and the LED, with the sound getting higher or more urgent as the signal gets stronger.

Please add simple controls. Left and Right should change sensitivity so I can tune out background noise. OK should cycle between sound plus vibration, sound only, vibration only, and silent. Up and Down should show and hide a help screen. Back should exit cleanly.

Make it ready to build as a Flipper Zero app and include the files needed to compile and install it. Look up current Flipper app docs online if you need to.