Zero-crossing counting was anti-correlated with the real defect (splice debris
fools it). Now asserts energy outside the fundamental, with an alignable control,
matching test_preserve_low_frequency.cpp's approach.
A splice can only relocate by [0.75, 1.25]*window, so periods with no multiple
in that interval never phase-align — at 50 ms, f < 16 Hz and 26.7-32 Hz.
Harness runs by hand; too slow to gate.
Re-derives the splice-cadence inequality and adds a corner probe that FAILS at
P=500 by design, pending a ruling. Names the baseline commit and harness edit,
fixes measurement methodology, corrects the Trigger-AHD/rate coupling framing.
Generalizes the correlation-aligned SOLA delay line so the feed and the shift are
independent rates over one ring. Unity is bit-identical to the shipped read, asserted
against a hash baseline captured pre-change.
daniel