fix: add diagnostic logging and OpenRouter language code filter

Add transcribe-start/complete logs for both providers, error response body logging, and ASR provider in startup log. Filter yue (ISO 639-3) language code from OpenRouter STT requests.

Ultraworked with Sisyphus

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

backend/app/services/asr_providers.py

@@ -39,6 +39,10 @@ class DashScopeASRProvider(ASRProvider):
 
     async def transcribe(self, audio_bytes: bytes, language: str) -> str:
         loop = asyncio.get_running_loop()
+        logger.info(
+            "asr-transcribe-start provider=dashscope model=%s audio_bytes=%d language=%s",
+            self._model, len(audio_bytes), language,
+        )
         return await loop.run_in_executor(
             None, self._transcribe_sync, audio_bytes, language
         )
@@ -92,6 +96,10 @@ class OpenRouterASRProvider(ASRProvider):
 
     async def transcribe(self, audio_bytes: bytes, language: str) -> str:
         audio_b64 = base64.b64encode(audio_bytes).decode("ascii")
+        logger.info(
+            "asr-transcribe-start provider=openrouter model=%s url=%s audio_bytes=%d language=%s",
+            self._model, self._stt_url, len(audio_bytes), language,
+        )
 
         payload: dict = {
             "model": self._model,
@@ -100,7 +108,10 @@ class OpenRouterASRProvider(ASRProvider):
                 "format": "wav",
             },
         }
-        if language and language != "auto":
+        # OpenRouter STT expects ISO-639-1 (2-letter) codes.
+        # DashScope languages like "yue" (Cantonese, ISO-639-3) are not valid here.
+        # Omit to let auto-detection handle it.
+        if language and language not in ("auto", "yue"):
             payload["language"] = language
 
         try:
@@ -112,6 +123,10 @@ class OpenRouterASRProvider(ASRProvider):
         if not text:
             raise ASRError("OpenRouter STT returned empty transcription")
 
+        logger.info(
+            "asr-transcribe-complete provider=openrouter text_len=%d",
+            len(text),
+        )
         return _to_traditional(text)
 
     @retry(
@@ -123,6 +138,12 @@ class OpenRouterASRProvider(ASRProvider):
     async def _call_stt_api(self, payload: dict) -> dict:
         client = await self._get_client()
         response = await client.post(self._stt_url, json=payload)
+        if response.status_code >= 400:
+            logger.error(
+                "openrouter-stt-error status=%d body=%s",
+                response.status_code,
+                response.text[:500],
+            )
         response.raise_for_status()
         return response.json()
 
@@ -134,8 +155,16 @@ class OpenRouterASRProvider(ASRProvider):
 
 def create_asr_provider(settings) -> ASRProvider:
     provider_name = settings.asr_provider
+    logger.info(
+        "asr-provider-selected provider=%s dashscope_key=%s openrouter_key=%s llm_base_url=%s",
+        provider_name,
+        "set" if settings.dashscope_api_key else "empty",
+        "set" if settings.openrouter_api_key else "empty",
+        settings.llm_base_url,
+    )
 
     if provider_name == "dashscope":
+        logger.info("asr-provider-init provider=dashscope model=%s", settings.asr_model_name)
         return DashScopeASRProvider(
             api_key=settings.dashscope_api_key,
             model=settings.asr_model_name,
@@ -147,6 +176,11 @@ def create_asr_provider(settings) -> ASRProvider:
                 "OPENROUTER_API_KEY is not configured. "
                 "Set it in .env to use OpenRouter ASR."
             )
+        logger.info(
+            "asr-provider-init provider=openrouter model=%s url=%s",
+            settings.asr_openrouter_model,
+            f"{settings.llm_base_url.rstrip('/')}/audio/transcriptions",
+        )
         return OpenRouterASRProvider(
             api_key=settings.openrouter_api_key,
             base_url=settings.llm_base_url,