meat/docs/adr/0001-engine-owns-world-concepts.md

Engine owns world concepts

Engine owns contracts and reusable mechanisms for levels, terrain, actors, prefabs, collision, scene rendering, chunking, LOD, and render transport; game owns concrete level values and concrete actor or prefab definitions. Game content is referenced through definition objects, never closed MobKind, TreeKind, or equivalent content registries; finite engine capability unions remain allowed. A live Level may contain behavior, while its RenderScene projection contains only clone-safe data for workers, with numeric prototype indexes confined to engine transport.