fix: review fixes — cache Wikidata calls, add timeout, improve escaping, hide empty popovers

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

assets/react/controllers/ActorPopover.jsx

@@ -21,6 +21,8 @@ export default function ActorPopover({ hintType, hintText }) {
     const dismiss = useDismiss(context);
     const { getReferenceProps, getFloatingProps } = useInteractions([click, dismiss]);
 
+    if (!hintText) return null;
+
     const iconClass = HINT_ICONS[hintType] || 'fa-solid fa-circle-question';
 
     return (