Changes:

Infinite scroll filtering now handles multiple sibling #albums feed sections by scanning all recognized roots and observing #page with document.body fallback. The single-root assumption was removed from content/site.js and content/main.js.
Highlights are stronger, thumbnail-only, and pulsing, with configurable color and intensity via schema v5 in shared/config.js, CSS custom properties in content/ui/styles.css, and controls in options/options.html and options/options.js.
Added simple categories management with id, name, term, favorite, favorites-first alphabetical ordering, same-tab open, clear new-tab action, edit, and delete. The in-page categories sheet is in content/ui/floating.js; settings-page management is in the options files.