Stage 4 of the page builder: all shop pages now render via
PageRenderer instead of inline templates or PageTemplates.
- Collection: full filter bar moved to renderer (category pills,
sort dropdown, CollectionFilters hook, empty state)
- PDP: related_products and reviews loaded via block data loaders
instead of manual queries
- Cart: page definition loaded in mount, subtotal computed in render
- Search: page definition loaded in mount, handle_params unchanged
- Added Phoenix.VerifiedRoutes to PageRenderer for ~p sigil
- Net -55 lines (128 added, 183 removed)
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>