refactoring folders

lib/elixir_ai/cluster_singleton/singleton_pg.ex

@@ -0,0 +1,16 @@
+defmodule ElixirAi.SingletonPG do
+  @moduledoc """
+  Named :pg scope for tracking cluster singleton processes across the cluster.
+  Each singleton joins {:singleton, __MODULE__} on init; :pg syncs membership
+  automatically and removes dead processes without any additional cleanup.
+  """
+
+  def child_spec(_opts) do
+    %{
+      id: __MODULE__,
+      start: {:pg, :start_link, [__MODULE__]},
+      type: :worker,
+      restart: :permanent
+    }
+  end
+end