[feature] Real time
For audio sequence should be provided a timecode.
We can use a  tick of update, but how i know it depend of RAF frequency, and we can't sync a APU with update for sequencing.

I know that WASM export a `seed` function that really is Date.now, and this already can be used, but is hacky.

maybe we can provide a `time` function same way?

UPD, i see that now we use a clamped update, and it should runs about 60 frames on any screens, exclude a iOS in power-save mode (it ticks 30 FPS)

https://github.com/aduros/wasm4/blob/main/runtimes/web/src/index.js#L343

