Adds POST /quantity/<product_id>/ to set cart item quantity (or remove at 0), and registers cart_quantity_url Jinja global so the shared template uses it. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Adds POST /quantity/<product_id>/ to set cart item quantity (or remove at 0), and registers cart_quantity_url Jinja global so the shared template uses it. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>