The TTS pads every sentence with 0.4-0.9 s of silence; boundaries are exact but the
highlight lit up that long before the words. Record per-sentence speech onsets at render
time, measure them from the decoded MP3 for older audio, and expose them as 'speech' in
/timings.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
