Add and apply Rails/EnumHash rubocop rule

In rubocop-rails 2.26.0, support was added for Rails 7 syntax in the
Rails/EnumHash rule. We took this opportunity to ensure consistency
by converting all enums to hash with integer values. This format minimizes
the risk of data consistency issues in the database when adding new values.

.rubocop.yml

@@ -388,6 +388,9 @@ Rails/DynamicFindBy:
     - find_by_slug_or_id!
     - find_by_manager_login
 
+Rails/EnumHash:
+  Enabled: true
+
 Rails/EnumSyntax:
   Enabled: true