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/__init__.py

@@ -114,10 +114,12 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
     await _safe_announce(manager)
     _schedule_periodic(hass, entry, runtime)
 
-    # Poll interface status.
+    # Poll interface status. refresh_interface_status is a @callback, so pass it
+    # directly (a lambda would be a plain sync job and get run in an executor
+    # thread, where its async_dispatcher_send call is not thread-safe).
     runtime.unsubs.append(
         async_track_time_interval(
-            hass, lambda _now: manager.refresh_interface_status(), INTERFACE_POLL
+            hass, manager.refresh_interface_status, INTERFACE_POLL
         )
     )