network_backend: use resolved device name in console output

NetworkBackend's connect/send/lost/error prints always used the
connect-time registration name, so GUI console output kept showing
the placeholder counter ID even after MON-VER resolved the real
device name. Add a display_name per socket (defaults to name, kept
separate from the routing key used by find_by_name/register_xcvr) and
have the GUI update it once MON-VER responds.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XM4FNUjhu9x8df5Dp1hHvd

gui/data_model.py

@@ -253,7 +253,7 @@ class ReceiverManager(QObject):
         state = self._states.get(rid)
         if not state or not state.connected:
             return
-        print(f"Receiver '{rid}': connection lost")
+        print(f"Receiver '{self.display_name(rid)}': connection lost")
         self.remove_receiver(rid)
 
     def disconnect_receiver(self, rid: str):
@@ -340,6 +340,9 @@ class ReceiverManager(QObject):
         if state:
             state.device_id  = device_id
             state.sw_version = sw_version
+            set_name = getattr(state.backend, 'set_display_name', None)
+            if device_id and callable(set_name):
+                set_name(rid, device_id)
         config = self._configs.get(rid)
         if config and device_id:
             config.receiver_id = device_id