improvement: support :ci_string as a storage_type

lib/migration_generator/migration_generator.ex

@@ -2743,6 +2743,7 @@ defmodule AshPostgres.MigrationGenerator do
   end
 
   defp migration_type_from_storage_type(:string), do: :text
+  defp migration_type_from_storage_type(:ci_string), do: :citext
   defp migration_type_from_storage_type(storage_type), do: storage_type
 
   defp foreign_key?(relationship) do

lib/types/ci_string_wrapper.ex

@@ -1,14 +1,14 @@
-defmodule Ash.Type.StringWrapper do
+defmodule Ash.Type.CiStringWrapper do
   @moduledoc false
   use Ash.Type
 
   @impl true
-  def storage_type(_), do: :text
+  def storage_type(_), do: :citext
 
   @impl true
-  defdelegate cast_input(value, constraints), to: Ash.Type.String
+  defdelegate cast_input(value, constraints), to: Ash.Type.CiString
   @impl true
-  defdelegate cast_stored(value, constraints), to: Ash.Type.String
+  defdelegate cast_stored(value, constraints), to: Ash.Type.CiString
   @impl true
-  defdelegate dump_to_native(value, constraints), to: Ash.Type.String
+  defdelegate dump_to_native(value, constraints), to: Ash.Type.CiString
 end

lib/types/string_wrapper.ex

@@ -0,0 +1,14 @@
+defmodule Ash.Type.StringWrapper do
+  @moduledoc false
+  use Ash.Type
+
+  @impl true
+  def storage_type(_), do: :text
+
+  @impl true
+  defdelegate cast_input(value, constraints), to: Ash.Type.String
+  @impl true
+  defdelegate cast_stored(value, constraints), to: Ash.Type.String
+  @impl true
+  defdelegate dump_to_native(value, constraints), to: Ash.Type.String
+end