Get Tts Catalog

Return the multi-provider catalog of available TTS voices.

Shape: { "languages": {"en": "English", ...}, "providers": { "deepgram": { "label": "Deepgram", "enabled": true, "supports_runtime": true, "runtime_note": null, "reason": null, "voices": [{provider, voice_id, label, language_codes, ...}, ...] }, ... } }