feat(frontend): rewrite editor as Premiere-style NLE + fix card overflow

feat(i18n): polish JA/ZH/KO translations for natural phrasing

feat(frontend): full UI redesign + fix editor navigation bug

feat(frontend): redesign editor workspace controls

fix(frontend): polish locale controls and editor layout

fix(frontend): complete locale dictionaries

feat(frontend): redesign product demo workspace

fix(frontend): import React for JSX runtime

feat(frontend): add human-ai clip editor