Sustained near-digital quiet on the overall level (< 0.006 for 300 ms,
sticky until a decisive 0.015) now places an immediate HOLD on the beat
tracker: nothing fires (real or predicted -- previously the predictor
kept faking beats for up to ~2 s into any silence), the tempo estimate
and confidence freeze exactly where they are, and beatphase freezes for
scripts instead of saturating at 'beat imminent'. Decisive audio
releases the hold instantly and the grid resumes from the phase the
audio went quiet (captured before the debounce window, so a
pause/resume keeps perfect time); after a hard cut the comb + first
real beats re-align within a couple of periods. 'Set Beat' taps release
the hold outright. Waveform/band data is never gated -- it still flows
(it is simply ~0, because the audio is gone).
- BeatFrame.silent carries the state; scripts get the silent variable
(1 while held); the beat indicator shows an amber HOLD badge + amber
phase ring while held.
- rust-agent/src/beat.rs + engine.rs: same gate ported for parity (its
bass level doubles as the silence signal; NOT compile-verified -- no
cargo in this sandbox).
- Verified: headless 26/26 assertions on the real BeatTracker (music ->
silence -> in-phase resume -> onsetless pad -> tap; the pre-fix
fake-beat window 12.8-15.5 s is empty) and browser E2E on the live
app with a generated 120 BPM + silence looping WAV (HOLD badge tracks
the silent spans exactly across two loop cycles; console clean).
