bootstrap.layout.type (the 'Site Layout' selector in the theme editor)
was only ever consulted by a validator checking it against the known
list - nothing used it to actually pick a layout. SectionEngineService
already resolves a per-page layout.type with a hardcoded 'default'
fallback; that fallback now reads the site-wide setting first.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
