Text-to-speech conversion using OpenAI's TTS API for generating high-quality, natural-sounding audio.
Supports 6 voices (alloy, echo, fable, onyx, nova, shimmer), speed control (0.25x-4.0x),
HD quality model, multiple output formats (mp3, opus, aac, flac), and automatic text chunking
for long content (4096 char limit per request).
Use when: (1) User requests audio/voice output with triggers like "read this to me",
"convert to audio", "generate speech", "text to speech", "tts", "narrate", "speak"