fix: remove dead code config.get experience

src/api/toolchain_routes.py

@@ -28,7 +28,7 @@ from src.blackboard.models import Task
 from src.blackboard.operations import Blackboard
 from src.config.agents import AGENT_IDS
 from src.daemon.toolchain_templates import render_template
-from src.utils import get_data_root
+import src.utils as _utils
 
 logger = logging.getLogger(__name__)
 
@@ -146,7 +146,7 @@ MAIL_PROJECT_ID = "_mail"
 
 def _mail_db_path() -> Path:
     """获取 Mail 数据库路径，确保目录存在。"""
-    root = get_data_root()
+    root = _utils.get_data_root()
     db = root / MAIL_PROJECT_ID / "blackboard.db"
     db.parent.mkdir(parents=True, exist_ok=True)
     init_db(db)