Add mock-backend VoiceEmbed/VoiceVerify (deterministic DC-offset speaker
discrimination) and a verify-mode gated realtime pipeline, then drive the
real HTTP/WS stack: an authorized speaker reaches response.done while an
unauthorized one is dropped before the LLM with a speaker_not_authorized
event.
Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Co-authored-by: Ettore Di Giacinto <mudler@localai.io>
