Two edge-drawing refinements (owner), both pure post-processing in
edgePathD on dagre's waypoints:
- Docking gap (4 units ≈ half a head length): the head's tip floats
short of the target face instead of touching it — the mouth pulls
back by tip overhang + gap, so the head kisses nothing and tilted
entries stop biting into the box.
- Shaft stub (12 units ≈ 1.5 head lengths): from Q, every control
point sits exactly on the approach line, so the basis spline renders
that stretch perfectly straight and the head lands on a straight
shaft; the corner where the route squares up is rounded by the
curve, and the repeated mouth point makes the end tangent exactly
the approach direction. Collinear routes render identically
(pinned: on-axis start to mouth).
Angle alignment/perpendicular entry deliberately NOT touched yet —
owner wants to evaluate this first (round 13 candidate).