edge_decode.py: the edge payloads' non-float words carry the plane constant/
vertex terms as .8 fixed-point screen coordinates (0x0000ec00 = 60416 = 236.0,
a screen-x in the object's range), not IEEE floats -- which is why they weren't
in the float list. Locates the last missing piece for edge reconstruction:
A/B slope (float, verified 0.2%) + C (fixed-point coord). Readout §02 notes it.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
