Add listening examples: round-trip ladder + screened d0 pair

Rewrite model card: lead with audio, tighten prose, re-measure on screened koan ladder

Add listening examples: round-trip ladder + screened d0 pair

Card: pair the depth result with a content-preservation measure

Card: depth curve, and state the low-depth metric gap plainly

SAME-L decoder LoRA (squeakfix_v3): round-trip artifact fix

initial commit