Add arXiv / HF / License badges to model card

Add arXiv link (2605.14231)

Add self-contained preprocess() with per-variant defaults

Set base_model to AudioMosaic-vit-b16-pretrained

Rename AudioMosaicSimCLR -> AudioMosaicPretrain

Initial release: AudioMosaic-vit-b16-finetune-esc-split2

initial commit