manag veth directly with sniffer

backend/src/main.py

@@ -75,6 +75,13 @@ async def on_startup() -> None:
 @app.on_event("shutdown")
 async def shutdown_event() -> None:
     """Stop network resources and release shared runtime objects."""
+    try:
+        from src.network_sniffer import stop_afpacket_sniffer
+
+        stop_afpacket_sniffer()
+    except Exception:
+        logging.exception("Failed to stop sniffer sessions during shutdown")
+
     try:
         network_api.shutdown_network_api()
     except Exception:
@@ -87,6 +94,13 @@ async def shutdown_event() -> None:
     except Exception:
         logging.exception("Failed to stop bridge telemetry collector")
 
+    try:
+        from src.utilities.capture_pipeline import capture_pipeline_manager
+
+        capture_pipeline_manager.stop_all()
+    except Exception:
+        logging.exception("Failed to stop capture pipelines")
+
     try:
         from src.utilities.packet_tracker import packet_tracker