L1 filename (sample_meta) → L3 audio fallback (sample_classify ensemble-fine, the
73% scoreboard winner) → L2 folder cross-check (flags folder_agrees=False when the
folder name lies). Audio runs ONLY on opaque files. Per folder: dominant, agreement
conf, homogeneous, kit_like, per-:index labels with source, provenance. Validates
the domain knowledge mechanically: jazz=kit (000_BD→kick :0, HH/OH→hat, SN→snare),
cpluck=multisample (plucks+body, folder='keys' flagged), 808hc=perc via audio.