Feature Day-2 ONNX repos (bass/other/vocals + bag)

Feature htdemucs-ft-drums-onnx (Day 1 of the ONNX project)

Add 3 stem-specialist repos to assets table

docs: feature StemSplitio/htdemucs-ft-pytorch model

docs: link to Music Source Separation Toolkit 2026 collection

feat: initial org card

initial commit