refactor: consolidate shop and preview page templates
- Create shared PageTemplates module in components/page_templates/
- Shop LiveViews now use explicit render/1 calling shared templates
- Theme preview now uses preview_page/1 component calling shared templates
- Delete duplicate preview_pages directory and shop_live/*.html.heex
- Single source of truth: mode param controls shop vs preview behavior
Templates: home, about, contact, collection, pdp, cart, error
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Jamey Greenwood
c25953780a