Fish Audio models now available on Vercel AI Gateway for free

Four Fish Audio models — s2.1-pro, s2-pro, s1 (text-to-speech) and transcribe-1 (speech-to-text) — are free on AI Gateway for 30 days, through September 18. s2.1-pro clones a voice from a reference recording; adding a "-free" suffix to a model name stops serving when the offer ends.