feat: add ASR provider support for voice co-creation

backend/app/services/provider_router.py

@@ -113,6 +113,14 @@ def _get_default_config(adapter_name: str) -> AdapterConfig | None:
             timeout_ms=1000,
         )
 
+    # --- ASR Defaults ---
+    if adapter_name == "openai_asr":
+        return AdapterConfig(
+            api_key=settings.openai_api_key,
+            model=settings.voice_transcription_model,
+            timeout_ms=60000,
+        )
+
     # --- Text Defaults ---
     if adapter_name in ("gemini", "text_primary"):
         return AdapterConfig(
@@ -289,7 +297,7 @@ async def _route_with_failover(
     """通用 provider failover 路由。
 
     Args:
-        provider_type: 供应商类型 (text/image/tts/storybook)
+        provider_type: 供应商类型 (text/image/tts/storybook/asr)
         strategy: 路由策略
         db: 数据库会话（可选，用于指标收集和熔断检查）
         user_id: 用户 ID（可选，用于成本追踪和预算检查）
@@ -297,7 +305,14 @@ async def _route_with_failover(
         story_id: 故事 ID（可选，用于关联 provider 事件）
         **kwargs: 传递给适配器的参数
     """
-    providers = await _get_providers_with_config(provider_type)
+    provider_names = kwargs.pop("provider_names", None)
+    if provider_names:
+        providers = [
+            (name, _get_default_config(name) or AdapterConfig(api_key=""), None)
+            for name in provider_names
+        ]
+    else:
+        providers = await _get_providers_with_config(provider_type)
 
     if not providers:
         raise ValueError(f"No {provider_type} providers configured.")
@@ -457,6 +472,35 @@ async def _route_with_failover(
     raise ValueError(f"No {provider_type} provider succeeded. Errors: {' | '.join(errors)}")
 
 
+async def transcribe_audio(
+    audio_bytes: bytes,
+    file_name: str | None = None,
+    mime_type: str | None = None,
+    transcript_hint: str | None = None,
+    language: str | None = None,
+    provider_names: list[str] | None = None,
+    strategy: RoutingStrategy = RoutingStrategy.PRIORITY,
+    db: AsyncSession | None = None,
+    user_id: str | None = None,
+):
+    """语音转写，支持 provider failover。"""
+    from app.services.adapters.asr.models import TranscriptionOutput
+
+    result: TranscriptionOutput = await _route_with_failover(
+        "asr",
+        strategy=strategy,
+        db=db,
+        user_id=user_id,
+        audio_bytes=audio_bytes,
+        file_name=file_name,
+        mime_type=mime_type,
+        transcript_hint=transcript_hint,
+        language=language,
+        provider_names=provider_names,
+    )
+    return result
+
+
 async def generate_story_content(
     input_type: Literal["keywords", "full_story"],
     data: str,