Introduce the `Plus` alpha composition mode and add support for ColorDodge, ColorBurn, SoftLight, Difference, Exclusion, Hue, Saturation, Color, and Luminosity across straight-alpha and associated-alpha pixel blenders. The generated blender/function tables and selector logic were updated to expose the new combinations, and tests were expanded to cover mode mapping, expected blend results, and parity between straight and premultiplied alpha paths.
James Jackson-South
c9af728104