Simulates a particle system inside the Worker and renders it to an animated GIF with the in-house encoder: five presets (fountain, fireworks, snow, smoke, orbit) with point, line, ring and burst emitters; gravity, wind, drag, Perlin-noise turbulence and a central attractor; soft additive particles with fading trails. Every parameter can be overridden, the seed makes runs reproducible, and the preview plays the loop. Size × frames is capped so a render fits the 5-second Worker limit.