CesiumJS Models, glTF & Particle Effects

Version baseline: CesiumJS v1.142.

Quick Reference

Class	Purpose
`Model`	Low-level glTF/GLB primitive; positioned via `modelMatrix`
`ModelAnimation`	Active animation instance on a model
`ModelAnimationCollection`	Collection at `model.activeAnimations`
`ModelNode`	Named node with modifiable transform
`ModelFeature`	Per-feature styling/picking for feature-ID models
`EdgeDisplayMode`	Controls draft glTF edge-visibility rendering on Model/Cesium3DTileset
`ParticleSystem`	Billboard-based particle manager (fire, smoke, rain)
`Particle`	Single particle with position, velocity, life
`ParticleBurst`	Scheduled burst of particles
`BoxEmitter` / `CircleEmitter`	Emit within box volume / flat disk
`ConeEmitter` / `SphereEmitter`	Emit from cone tip / within sphere