Hydra V1.1 - configurable output sample rate, nine British English voices

Two changes ship for hydra-v1.1 today.

Output audio sample rate is now configurable. Set session.output_audio_sample_rate in your first session.configure to get reply audio at the rate you need - a 16 kHz telephony leg, for example, no longer needs its own resampling step:

{
  "type": "session.configure",
  "session": {
    "output_audio_sample_rate": 16000
  }
}

Accepted values: 8000, 16000, 22050, 24000, 32000, 44100, 48000 Hz.
Leave it out and audio arrives at 24000 Hz, as before.
The rate you’ll get is confirmed in session.configured.session.output_audio_sample_rate - read it from there rather than assuming the value you sent was honored.
An unsupported value is rejected with error (code: "invalid_request_error", param: "session.configure.session.output_audio_sample_rate").
Input audio is unaffected - the caller audio you send stays 16 kHz PCM16 mono.
hydra-v1.0 does not support this field; its output stays fixed at 48000 Hz.

Nine British English voices join the roster. Pick one with voice in session.configure, using the lowercase ID:

Accent	Voice ID
British English (female)	`arabella`, `cressida`, `elowen`, `sophie`
British English (male)	`callum`, `caspian`, `cormac`, `everett`, `rupert`

The ten existing hydra-v1.1 voices (zoe, maya, elena, ivy, grace, alex, aria, leo, sam, kai) are unchanged, bringing the hydra-v1.1 roster to nineteen voices. An unrecognised voice is still rejected with an error frame (code: "invalid_request_error").

Migration: no action - existing integrations that don’t set output_audio_sample_rate keep getting 24000 Hz, and existing voice IDs keep working unchanged. See the Hydra model card and Audio I/O for details.