faster-whisper accepts `turbo` and the config docs listed it, but the CLI
picker, dashboard and Desktop settings stopped at large-v3, so the only way to
use it was hand-editing config.yaml. All three now read it from the shared
STT_MODEL_CATALOG, along with the install hint and the cloud-model warning.
Salvage of #79671 by @tank321, rebased onto the unified catalog from #133825.