unknown_focus_type· reason_code· applies to service_call, schema_validationA `ak.realm.media_service.foci[].focus_kind` value is not in the v1 registered set (`livekit` / `mediasoup` / `janus` / `arkret_native` / `moq_relay`) or is registered but not supported by this client / issuer. Clients MUST fail closed instead of forwarding the token to an arbitrary SDK. See zh/crypto-media/media-service-binding.md §2.