Add current_actor/1 helper for consistent actor access

Provides a single function to access current_user from socket assigns
across all LiveViews, ensuring consistent access pattern.

lib/mv_web/live_helpers.ex

@@ -59,4 +59,19 @@ defmodule MvWeb.LiveHelpers do
         user
     end
   end
+
+  @doc """
+  Helper function to get the current actor (user) from socket assigns.
+
+  Provides consistent access pattern across all LiveViews.
+  Returns nil if no current_user is present.
+
+  ## Examples
+
+      actor = current_actor(socket)
+      members = Membership.list_members!(actor: actor)
+  """
+  def current_actor(socket) do
+    socket.assigns[:current_user] || socket.assigns.current_user
+  end
 end