Grows Vector2/3, Mathf, Color, Quaternion, GameObject, Transform, Camera, Material,
ParticleSystem, Rect, Bounds, Time to the surface the engine references; adds Input/
Random/Resources statics + full KeyCode enum. Copies the verbatim extension files that
collapse thousands of CS1061s at once (ContentKeywordExt, JsonData/LitJson extensions,
EventExtension.Call, GameObjectExtension(s)). 26.5k -> 15.9k errors; residual now
dominated by god-object member surface (GameMgr/UIManager/EffectMgr/Vfx*).
