Extract existing delegated cleanup from index into one cohesive helper and reconcile finished interface CSS animations when initialization arrives after animationend. Preserve active/replacement effects, future end/cancel events, thumbnail eligibility and unrelated classes. No CSS or other bootstrap changes.
New17 controlled scenarios including real isolated index cleanup wiring;19distinct mutants killed/all17casescovered, full lint11pass. Existing assertions unchanged. Full gate, build and native point validation still require separate slots.