AF_PACKET terminology cleanup

backend/src/main.py

@@ -82,11 +82,11 @@ async def on_startup() -> None:
 async def shutdown_event() -> None:
     """Stop network resources and release shared runtime objects."""
     try:
-        from src.network_sniffer import stop_afpacket_sniffer
+        from src.network_sniffer import stop_capture_session
 
-        stop_afpacket_sniffer()
+        stop_capture_session()
     except Exception:
-        logging.exception("Failed to stop sniffer sessions during shutdown")
+        logging.exception("Failed to stop capture sessions during shutdown")
 
     try:
         network_api.shutdown_network_api()