test(baselines): regenerate for #216 pixel-edge extent shift

Datashader points/shapes, image-extent, and a few image baselines shift by the
half-pixel correction (sub-tolerance for large images, hence only 32 of them).
Adds the baseline for the new centroid-alignment visual test. Regenerated from
CI artifacts (py3.11-stable; 31/32 byte-identical to py3.14-stable).

Author: timtreis