fix(deploy): reduce backend worker footprint

backend/src/v1/agent/asr.py

@@ -3,9 +3,6 @@ from __future__ import annotations
 import asyncio
 from typing import Any
 
-import dashscope
-from dashscope.audio.asr import Recognition, RecognitionCallback
-
 from core.config.settings import config
 from core.logging import get_logger
 
@@ -28,6 +25,9 @@ class AsrService:
 
     async def transcribe_file(self, file_path: str, filename: str) -> str:
         try:
+            import dashscope
+            from dashscope.audio.asr import Recognition, RecognitionCallback
+
             dashscope.api_key = self._get_api_key()
 
             loop = asyncio.get_event_loop()