@hatch:postfx v0.1.0

Common post-processing effects for the WrenLift game framework. Tonemap, Vignette, Bloom, FXAA, ColorGrade, ChromaticAberration — each a PostPass subclass that drops into g.postFX = PostFX.new(g) from @hatch:game. Effects ship here so the engine stays lean; new effects can be added without bumping @hatch:game.