Add preview_token to pages

New column + unique index, plus ensure_preview_token!/revoke_preview_token!
on Page. Generated lazily (only when explicitly requested) rather than
via has_secure_token's default auto-generate-on-create, so a live,
shareable secret isn't silently minted for every page ever created.

1 files changed, 6 insertions, 0 deletions

diff --git a/db/migrate/20260706030547_add_preview_token_to_pages.rb b/db/migrate/20260706030547_add_preview_token_to_pages.rb
new file mode 100644
index 0000000..794cbb2
--- /dev/null
+++ b/db/migrate/20260706030547_add_preview_token_to_pages.rb
@@ -0,0 +1,6 @@
+class AddPreviewTokenToPages < ActiveRecord::Migration[8.1]
+  def change
+    add_column :pages, :preview_token, :string
+    add_index :pages, :preview_token, unique: true
+  end
+end