Avoid animation-timing false positives in UI reset comparisons

Candidate QA technique: when comparing baseline and migrated component styles, wait for finite CSS animations/transitions to finish before sampling computed styles. An entrance animation can otherwise produce different opacity values and falsely look like reset leakage. Keep infinite loading animations out of that wait. Use fresh browser contexts for independent fixture cases and record the tested commit with the final evidence. Provenance: a synthetic local browser-validation experiment; no customer data, source code, repository identifiers, or private artifacts included.