The check that a track plays through one shifter on its bus asked for
the start of the clip only after the note was planned. The clip ends
where the note starts, and the note is planned just 0.126 s ahead. In
a slow browser the clip's voice was already gone by then, and
`__gm.sound.startedAt` gave `null`.
- Each reading takes the plan, both starts and the audio clock in one
`evaluate`. The clock goes into the detail of the check.
- The start of the clip is kept from the first reading that has it.
Readings come every 150 ms plus the round trip, which is longer than
the 0.126 s window, so one reading alone would not be enough.
- The note's start is still read where the note is planned.
Tests:
- Prettier, eslint on 65-song.mjs: clean
- e2e 65 on melektaus-atx: ALL PASSED, 59 checks
- Bent check (wait until the clip is over, read the start as before):
red as the only one of 59, `clipStart: null` at clock 21.943 after
the clip ended at 21.828
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>