gigglemorgan/open-synthesia ? reverse-engineered prompt

Build me a lightweight piano practice app that runs in the browser and also works as a desktop app. I want a Synthesia style falling note view, an 88 key piano keyboard, and support for playing with a computer keyboard or a real MIDI keyboard, including sustain pedal support.

Please include practice features like wait mode where notes stop until I press the right keys, left hand, right hand, or both hands practice, loop a section between two points, and let me change tempo or speed. I also want a clean audio player with realistic piano sound, plus the ability to import a MIDI file and play it back, export MIDI to MP3, and turn audio files back into MIDI if possible.

Make it feel fast and smooth, handle very dense songs without lag, and include English and Turkish language switching. If you need current docs for browser MIDI or audio APIs, look them up online.