Calculate optimal word_duration based on actual TTS audio duration and text punctuation.
- server/services/ttsSync.ts: new service to measure TTS audio and compute sync timing
- server/routes/reels.ts: integrate sync into preview and background processing
- client: auto-calculate sync info widget in desktop and mobile Reel creation
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
