Every GalleryOptions/plugin-option field as a live form below the gallery — flip
settings, pick dynamic (JSON items) vs. selector (DOM markup) mode, and the gallery rebuilds
itself immediately, no separate step. All 24 items are generated inline (SVG placeholders, one
real HTML5 video, one YouTube link, one Vimeo link) — no external image assets, so this page
has no dependency beyond dist/ and one small sample clip.