Function is_bouncy_simd 

pub fn is_bouncy_simd(restitution: SimdReal, is_new: SimdReal) -> SimdReal

Should a contact be treated as bouncy? (SIMD lanes; 1.0 = bouncy.) Restitution is per-manifold (ContactManifoldData::restitution); is_new is decoded from bit 31 (NEW_CONTACT_BIT) of SolverContactGeneric::contact_id.