refactor: extract ensure_user_role_loaded into shared on_mount hook

Move duplicate ensure_user_role_loaded logic into MvWeb.LiveHelpers
on_mount hook to eliminate code duplication across RoleLive modules
and centralize security-related user role loading.

lib/mv_web/live/role_live/form.ex

@@ -15,6 +15,8 @@ defmodule MvWeb.RoleLive.Form do
 
   alias Mv.Authorization.PermissionSets
 
+  on_mount {MvWeb.LiveHelpers, :ensure_user_role_loaded}
+
   @impl true
   def render(assigns) do
     ~H"""
@@ -87,8 +89,6 @@ defmodule MvWeb.RoleLive.Form do
 
   @impl true
   def mount(params, _session, socket) do
-    # Ensure current_user has role loaded for authorization checks
-    socket = ensure_user_role_loaded(socket)
 
     case params["id"] do
       nil ->
@@ -128,7 +128,10 @@ defmodule MvWeb.RoleLive.Form do
                |> redirect(to: ~p"/admin/roles")}
 
             {:error, error} ->
-              raise error
+              {:ok,
+               socket
+               |> put_flash(:error, format_error(error))
+               |> redirect(to: ~p"/admin/roles")}
           end
         rescue
           e in [Ash.Error.Invalid] ->
@@ -230,28 +233,10 @@ defmodule MvWeb.RoleLive.Form do
   defp return_path(_, role) when not is_nil(role), do: ~p"/admin/roles/#{role.id}"
   defp return_path(_, _role), do: ~p"/admin/roles"
 
-  defp ensure_user_role_loaded(socket) do
-    if socket.assigns[:current_user] do
-      user = socket.assigns.current_user
-      user_with_role = load_user_role(user)
-      assign(socket, :current_user, user_with_role)
-    else
-      socket
-    end
+  defp format_error(%Ash.Error.Invalid{} = error) do
+    Enum.map_join(error.errors, ", ", fn e -> e.message end)
   end
 
-  defp load_user_role(user) do
-    case Map.get(user, :role) do
-      %Ash.NotLoaded{} -> load_role_safely(user)
-      nil -> load_role_safely(user)
-      _role -> user
-    end
-  end
-
-  defp load_role_safely(user) do
-    case Ash.load(user, :role, domain: Mv.Accounts) do
-      {:ok, loaded_user} -> loaded_user
-      {:error, _} -> user
-    end
-  end
+  defp format_error(error) when is_binary(error), do: error
+  defp format_error(_error), do: gettext("An error occurred")
 end