"""TTSProvider port — 文字转语音能力契约。"""
from typing import Protocol, runtime_checkable
@runtime_checkable
class TTSProvider(Protocol):
async def synthesize(
self, text: str, voice: str = "alloy", *, language: str = "zh"
) -> bytes:
"""Convert text to speech audio bytes.
language: 'zh' or 'en' — 调用方应使用用户语言偏好(与正文语种无关);各 adapter 按自身能力解释。
"""
...