refactor: apply review changes to joinrequest

lib/membership/join_request/changes/set_confirmation_token.ex

@@ -2,11 +2,15 @@ defmodule Mv.Membership.JoinRequest.Changes.SetConfirmationToken do
   @moduledoc """
   Hashes the confirmation token and sets expiry for the join request (submit flow).
 
+  Uses `JoinRequest.hash_confirmation_token/1` so hashing logic lives in one place.
+
   Reads the :confirmation_token argument, stores only its SHA256 hash and sets
   confirmation_token_expires_at (e.g. 24h). Raw token is never persisted.
   """
   use Ash.Resource.Change
 
+  alias Mv.Membership.JoinRequest
+
   @confirmation_validity_hours 24
 
   @spec change(Ash.Changeset.t(), keyword(), Ash.Resource.Change.context()) :: Ash.Changeset.t()
@@ -14,7 +18,7 @@ defmodule Mv.Membership.JoinRequest.Changes.SetConfirmationToken do
     token = Ash.Changeset.get_argument(changeset, :confirmation_token)
 
     if is_binary(token) and token != "" do
-      hash = token_hash(token)
+      hash = JoinRequest.hash_confirmation_token(token)
       expires_at = DateTime.utc_now() |> DateTime.add(@confirmation_validity_hours, :hour)
 
       changeset
@@ -25,8 +29,4 @@ defmodule Mv.Membership.JoinRequest.Changes.SetConfirmationToken do
       changeset
     end
   end
-
-  defp token_hash(token) do
-    :crypto.hash(:sha256, token) |> Base.encode16(case: :lower)
-  end
 end