Where the instrument's loop grid, crossfade and pitch handling stop making
sense as a capture shrinks toward one cycle, and what "wavetable synth" would
mean here. Two structural results: the pre-seam crossfade is the identity map
at one-period loop lengths, and YIN cannot detect a single cycle, so the period
is declared rather than detected there. Four candidate shapes, W3 recommended
out. PLAN.md gets a pointer under "Flagged for awareness" only.
