Fetches and caches the kit.json manifest for a given kit ID (e.g. "bunker", "flakturm").
Resolves the meta.json spec sheet for a kit prop ID (e.g. "bunker/kerosene_lantern").
Loads a declarative level descriptor from JSON or a passed LevelDescriptor object, instantiating all props, lights, and environment elements into a parent root Object3D.
OptionaltargetScene: Object3D | { add(obj: Object3D): void }Loads a kit prop glTF, reads its meta.json, applies recommendedScale (unless overridden),
mounts socket lights, and applies level-instance transform/material overrides.
Manages modular asset kits, manifest resolution, meta.json parsing, socket light mounting, and declarative level loading according to ADR 0011 and ADR 0020.
Designed for pure Constructor Injection / Dependency Injection — strictly no global singletons.