Mirrors TruncFactor: inherent damped-propagate method, trait impl delegates with α=1.0. Existing goldens unchanged because cavity*new_msg equals the previous marginal write when α=1.0.
Mirrors TruncFactor: inherent damped-propagate method, trait impl delegates with α=1.0. Existing goldens unchanged because cavity*new_msg equals the previous marginal write when α=1.0.