feat: wait for enrolled sensors to announce, factory reset them on deletion

priv/repo/migrations/20260515115837_add_confirmed_to_sensors.exs

@@ -0,0 +1,9 @@
+defmodule Localiser.Repo.Migrations.AddConfirmedToSensors do
+  use Ecto.Migration
+
+  def change do
+    alter table(:sensors) do
+      add :confirmed, :boolean, default: false, null: false
+    end
+  end
+end