refactor: use explicit system config getter

app/agent/tools/impl/query_downloaders.py

@@ -7,7 +7,7 @@ from pydantic import BaseModel
 
 from app.agent.tools.base import MoviePilotTool
 from app.agent.tools.tags import ToolTag
-from app.application.configuration import get_configured_system_config as SystemConfigOper
+from app.application.configuration import get_configured_system_config
 from app.runtime.log import logger
 from app.schemas.types import SystemConfigKey
 
@@ -34,7 +34,7 @@ class QueryDownloadersTool(MoviePilotTool):
     @staticmethod
     def _load_downloaders_config():
         """从内存配置缓存中读取下载器配置。"""
-        return SystemConfigOper().get(SystemConfigKey.Downloaders)
+        return get_configured_system_config().get(SystemConfigKey.Downloaders)
 
     @staticmethod
     def _sanitize_downloaders_config(downloaders_config: list) -> list: