Building Riffly: from a hummed melody to a playable guitar idea

I keep losing small musical ideas. I will hum something, think "that might work on guitar", then forget enough of it before I have worked out the notes. I built Riffly to test whether a browser could shorten that gap: record a few seconds, turn the audio into a playable guitar idea, listen to the result, then save it for later. That sounds like a transcription problem. It is really three different problems: detect musical events in messy audio; map those events onto a physical guitar fretboard;