Momentum transfer collision response - full elastic collision.

Uses RAPIER-style dual solver architecture:

• resolveVelocity(): Apply velocity impulses (called multiple times per frame)
• resolvePosition(): Apply position correction (called once per frame with conservative factor)

Position correction is weighted by inverse mass (lighter bodies move more). Velocity impulse follows elastic collision formula with configurable restitution. Angular impulse applies torque from contact point offset (opt-in).