M3: Game Semantic Metadata

[TristinWen]

Goal

Compile semantic definitions into game-ready assets rather than model-only output.

Ordered scope

1. Generic anchors and sockets
2. Grips, weapon sockets, mount and interaction points
3. Damage zones and gameplay tags
4. Foot IK and grounding markers
5. Collider rules
6. LOD rules

Core remains engine-neutral; adapters create native components.

[TristinWen]

Implemented in b28ce6e, 784d7f0, and cf75cb1: portable anchors, sockets, grips, damage zones, tags, IK roles, colliders, LOD rules, Unity native compilation/runtime manifest, JSON/CLI workflow, and tests. All test assemblies compile; live EditMode execution remains pending.