HIGH RISK-001 : secondary comparator on def.id() prevents UB on
equal-priority items — no longer depends on BodyRegionV2 enum order.
New test asserts lexicographic ordering.
HIGH RISK-002 : resetLivingAnimations restores defaultLivingAnimations
snapshot. Javadoc now warns against calling setCurrentMotionsAsDefault
anywhere in the TiedUp pipeline (would leak custom bindings into
defaults, breaking unbind). Grep confirms no call site exists today.
Polish : rename tautological null test, precise null-safety doc.
e37dad18aa