bep/gallerydeluxe ? reverse-engineered prompt

Build me a fast Hugo photo gallery theme for a site with lots of images.

I want a clean gallery page that loads quickly, looks good on mobile and desktop, and can handle a big photo collection without feeling heavy. The gallery should support basic options like shuffling the image order, reversing it, and showing useful photo details when available. I also want an optional watermark on the large images, with simple positioning choices like left, center, or right and top, center, or bottom.

Please make it easy to drop into an existing Hugo site as a module, and include a simple example setup so I can see how to configure it and use it right away. If you need to check the latest Hugo docs for the best way to wire it up, go ahead and look them up.