fix: suppress bandit B404 warning on subprocess import in pytest_runner

app/tools/pytest_runner.py

@@ -2,7 +2,7 @@
 Runs pytest against a cloned repository inside a resource-limited sandbox.
 """
 import os
-import subprocess
+import subprocess   # nosec B404
 from typing import Any
 
 from app.core.logger import get_logger