AddedVelocityTrait
constAddedVelocityTrait:Trait<{launchCount:number;velocity: () =>Vector3; }>
A launch addLinearVelocity added to a body moveAndSlide moves,
which the body’s next tick’s first moveAndSlide reports as
addedVelocity and clears, so a kit folds a knockback into its own
velocity. Predicted, so a correction restores a launch not yet
consumed.