The per-call provider argument on text_to_speech (added via #73513,
closing #47459) let the model reroute speech to any configured backend,
contradicting the tool's own schema header ("Voice and provider are
user-configured ... not model-selected") and leaving compact channels
unable to keep a house voice without prompt-layer appendices.
- drop provider from the model-facing TTS_SCHEMA
- stop forwarding args["provider"] in the registry handler
- keep the function argument for internal/test callers, but a value
disagreeing with the configured tts.provider is now ignored with a
warning (both text_to_speech_tool and _text_to_speech_single)
Fixes#90109
5b671e29a4