## Why
Realtime v3 voice validation used the v1 voice list, limiting the available voice choices.
## What changed
- Add a dedicated `v3` voice list containing the v1 voices and 16 additional voices, and use it to validate v3 requests.
- Expose `v3` in `RealtimeVoicesList`, defaulting to an empty list when omitted during deserialization.
- Update the configuration and app-server schemas, generated TypeScript and Python types, and voice-list test expectations.
GitOrigin-RevId: 7fc8060fe01d840f28eb92c3dfe49c5878c3c258