Hardcoded negation of X/Y on input with no coordinate-system control

[XenonofArcticus]

Where: LoadPoints negates X and Y before AddPoint

Why it’s wrong: This unconditionally flips handedness/origin; if input is already in grid coordinates or has different convention, data is silently corrupted.

Evidence: DG->AddPoint(-A, -B, C); with commented rationale indicating WCS orientation, but no runtime control.
GitHub

Fix: Make this conditional or controlled by a flag; default should not mutate coordinates silently.