Sets up a Ghibli/anime post-processing chain for three.js EffectComposer — RenderPass → half-res GTAO (with additive/transparent objects hidden from it) → UnrealBloom with a linear-HDR threshold → optional underwater pass → split-tone colour grade (gold/peach highlights, teal shadows, saturation, warmth, vignette) → OutputPass → SMAA last.
