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/manifest.json

@@ -12,5 +12,5 @@
   "loggers": ["RNS", "LXMF"],
   "requirements": ["rns>=0.9.0", "lxmf>=0.6.0"],
   "single_config_entry": true,
-  "version": "1.0.4"
+  "version": "1.0.5"
 }