A homography-era assumption survived the migration: projectSegments warped only
segment endpoints. The polynomial warp bends a path at its vertices, so a straight
G0/G1 move (2 points) rendered as a straight chord, hiding all distortion correction
(measured ~320px of bow collapsed to nothing on bed-spanning lines). Resample edges to
20mm in work space before warping; arcs already had dense vertices so are unaffected.
