Run interface poll on the event loop (fix async_dispatcher_send off-thread)

The interface-status poll was registered as a plain lambda, so
async_track_time_interval ran it in an executor thread, where its
_push_state()->async_dispatcher_send() call tripped HA's thread-safety guard.

Make refresh_interface_status a @callback (it only reads fast in-memory
interface attributes) and pass it to async_track_time_interval directly.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

custom_components/reticulum/reticulum_client.py

@@ -612,10 +612,13 @@ class ReticulumManager:
     # ------------------------------------------------------------------
     # Helpers
     # ------------------------------------------------------------------
-    def refresh_interface_status(self) -> None:
+    @callback
+    def refresh_interface_status(self, now: Any = None) -> None:
         """Recompute interface online status and collect telemetry.
 
-        Called on the event loop from a periodic timer. RX/TX byte counters and
+        Decorated with @callback and used directly as the async_track_time_interval
+        action so it runs on the event loop (only fast in-memory interface
+        attribute reads happen here, no blocking I/O). RX/TX byte counters and
         bitrate are available for the TCP client interface; RSSI/SNR/quality are
         only populated when the underlying interface is a physical one (e.g. an
         RNode/LoRa interface) and stay ``None`` for a plain TCP link.