* feat(tts): support custom OpenAI-compatible TTS endpoints
Add OPENAI_TTS_BASE_URL environment variable to allow using self-hosted
or third-party OpenAI-compatible TTS services like Kokoro, LocalAI, or
OpenedAI-Speech.
Changes:
- Add OPENAI_TTS_BASE_URL env var (defaults to OpenAI official API)
- Relax model/voice validation when using custom endpoints
- Add tts-1 and tts-1-hd to the model allowlist
This enables users to:
- Use local TTS for privacy and cost savings
- Use models with better non-English language support (Chinese, Japanese)
- Reduce latency with local inference
Example usage:
OPENAI_TTS_BASE_URL=http://localhost:8880/v1
Tested with Kokoro-FastAPI.
* fix: strip trailing slashes from OPENAI_TTS_BASE_URL
Address review feedback: normalize the base URL by removing trailing
slashes to prevent double-slash paths like /v1//audio/speech which
cause 404 errors on some OpenAI-compatible servers.
* style: format code with oxfmt
* test: update tests for expanded OpenAI TTS model list
- Accept tts-1 and tts-1-hd as valid models
- Update OPENAI_TTS_MODELS length expectation to 3
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Co-authored-by: zhixian <zhixian@bunker.local>
