SSR denoising: three.js vs FidelityFX

Port of three.js's webgpu_postprocessing_ssr_denoise example (dungeon by Warkarma, stochastic SSR by 0beqz). Left: three's temporalReproject + recurrentDenoise. Right: the same SSR through ffxReflections() from denoiser/three (AMD FidelityFX reflection denoiser, WGSL). Each side has its own SSR node; the camera sways. Add ?ffxHistory=0 to stop feeding FFX's output back into SSR.