message scheduling + packaging improvements

[felixroos]

implement basic scheduling:

• add SCHEDULE_MSG and BATCH_MSG to schedule messages at a relative time in the future
• AudioView: add optional time argument to setControl to schedule control change
• AudioView: add setControls to batch change controls with a single message

example:

repl.audio.setControls([
  { id:'freq', time:onset, value: freq },
  { id:'gate', time:onset, value: 1 },
  { id:'gate', time:offset, value: 0 },
])

full strudel example

optimize package for integration (tested with strudel):

• SalatRepl: add localScope flag (opt in) to avoid global scope pollution. It's needed to avoid name collisions with strudel (like n)
• SalatRepl: remove base option, as worklet loading is now relative, inspired by Fix clock worker dependency path in module builds tidalcycles/strudel#1129 -> this also means no prebuild step is needed in the flok integration (hopefully)