{# The compare tray owns the ONLY handler for [data-cmp-add], and product-card
renders that button on every card in the store — so it has to be layout-level,
not product-template-level: the shopper compares from a collection grid. #}
{# defer, not script_tag: both run after parsing and keep their order, so
facets.js can rely on window.XGS.revealScan that global.js defines #}
