Numpy only; the resident worker is its one caller. Hips-relative, heading-normalised
poses; cost is pose RMS plus 0.1 s of velocity RMS; ties go to the longer window,
then the earlier. Tests: a periodic stride between rests, the stated cost against a
frame-by-frame oracle, heading, ties, minimum length.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
