Describe the current behavior

The product image zoom and media modal (lightbox) do not work when clicking on product images. The product images are visible, but clicking on them does not trigger any modal or zoom effect.
No JavaScript errors appear in the console, and the product-modal and modal-opener elements exist in the DOM.

Describe the expected behavior

Clicking on a product image or thumbnail should open the product media modal (lightbox) or zoom in on the image, as in previous Dawn versions.

Version information (Dawn, browsers and operating systems)

Theme version: Dawn 15.4.0
Storefront: Shopify Online Store 2.0
Environment: No custom apps or JS; clean theme install

Possible solution

Additional context/screenshots