Model calibration

Measure each unique GLB once with inspect-glb, only trusting bounds when boundsSource is vertices, and keep one tuning record per asset:

const ASSET_TUNING = {
    model: {
        boundsSource: 'vertices', dims: [8, 7, 18], center: [0, 2.5, 0], groundOffset: 1,
        intended: { dimension: 'length', size: 18 }, scale: 1, y: 1, yaw: 180
    }
} as const;