fix(Page): Only ensure_draft_version for new records

Skip the callback entirely for persisted records. New records still get
their draft_version built, while persisted records can use preloading or
lazy loading.

This fixes an issue with the preloaded page tree where the after_initialize
callback was triggering individual queries for each page's draft_version
during bulk loading, before Rails could apply preloading.

Author: tvdeyen

app/models/alchemy/page.rb

@@ -140,7 +140,7 @@ class Page < BaseRecord
     validates_format_of :page_layout, with: /\A[a-z0-9_-]+\z/, unless: -> { page_layout.blank? }
     validates_presence_of :parent, unless: -> { layoutpage? || language_root? }
 
-    after_initialize :ensure_draft_version
+    after_initialize :ensure_draft_version, if: :new_record?
 
     before_save :set_language_code,
       if: -> { language.present? }

spec/models/alchemy/page_spec.rb

@@ -135,6 +135,24 @@ module Alchemy
             expect(page.draft_version.meta_description).to eq("Test")
           end
         end
+
+        context "for persisted pages" do
+          let!(:persisted_page) do
+            create(:alchemy_page, language: language, parent: language_root)
+          end
+
+          let(:page) do
+            Alchemy::Page.find(persisted_page.id)
+          end
+
+          it "does not load draft_version association" do
+            expect(page.association(:draft_version)).not_to be_loaded
+          end
+
+          it "still provides draft_version when accessed" do
+            expect(page.draft_version).to be_present
+          end
+        end
       end
 
       context "before_save" do