Replace sync setState-in-effect with keyed remount and render-derived patterns in app, error-display, topbar-edit-modal, catalog-filters; use useCurrentTime() instead of Date.now() in hot paths; fix conditional hooks, passive scroll listeners, lodash path imports.
Replaced `import _ from 'lodash'` with specific named imports (`capitalize`, `lowerCase`, `debounce`, `startCase`) across 18 files. This reduces bundle size and improves tree-shaking efficiency.