manag veth directly with sniffer

backend/src/utilities/bridge_telemetry.py

@@ -54,6 +54,9 @@ class BridgeTelemetryManager:
 
         env = os.environ.copy()
         env["PYTHONUNBUFFERED"] = "1"
+        backend_root = str(helper.parents[2])
+        existing_pythonpath = env.get("PYTHONPATH", "")
+        env["PYTHONPATH"] = backend_root if not existing_pythonpath else f"{backend_root}:{existing_pythonpath}"
 
         cmd = [python_bin, str(helper), "--ifaces", ",".join(sorted(self._interfaces))]
         logger.info("Starting bridge telemetry collector for interfaces=%s", sorted(self._interfaces))