Add catch-all handler for unknown PubSub messages in PollerWorker

lib/towerops/snmp/poller_worker.ex

@@ -78,6 +78,12 @@ defmodule Towerops.Snmp.PollerWorker do
     {:noreply, state}
   end
 
+  @impl true
+  def handle_info(_msg, state) do
+    # Ignore other messages (like equipment status changes)
+    {:noreply, state}
+  end
+
   @impl true
   def handle_cast(:poll_now, state) do
     _ = perform_poll(state.equipment_id)