Taxonomy patch: relabel indices 79/80/81 (Hand Scratching Head, Hand Slaps, Slap Face) -> 'No burst' due to production false positives; weights unchanged
Label-mapping-only change. model.pt untouched, still 83 logits, indices intact so existing checkpoints/cached logits stay valid. class_to_group maps 'No burst'->no_burst. README documents original names+indices and raw-logit implications; supersedes the old 'Slap Face false positives' caveat.
README: document Slap Face top-1 false-positive mode and runner-up mitigation
