feat(editor): subtitle-first editor + AI subtitle pipeline

fix(editor): real-time drag via draft state + range-locked playback

fix(editor): kill empty band + first-frame preview + polish

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

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

feat(frontend): redesign editor workspace controls

fix(frontend): polish locale controls and editor layout

feat(frontend): redesign product demo workspace

feat(frontend): add human-ai clip editor