Add claimed to platform API user

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: asc-ioki

lib/ioki/model/platform/user.rb

@@ -9,6 +9,7 @@ class User < Base
         attribute :created_at, on: :read, type: :date_time
         attribute :updated_at, on: :read, type: :date_time
         attribute :analytics_tracking, on: [:read, :create], type: :boolean
+        attribute :claimed, on: [:read, :create], type: :boolean
         attribute :email,
                   type:             :object,
                   on:               [:read, :create, :update],

spec/ioki/model/platform/user_spec.rb

@@ -6,6 +6,7 @@
   it { is_expected.to define_attribute(:created_at).as(:date_time) }
   it { is_expected.to define_attribute(:updated_at).as(:date_time) }
 
+  it { is_expected.to define_attribute(:claimed).as(:boolean) }
   it { is_expected.to define_attribute(:email).as(:object).with(class_name: 'UserEmail') }
   it { is_expected.to define_attribute(:external_id).as(:string) }
   it { is_expected.to define_attribute(:first_name).as(:string) }