fix(ui): set MediaSource duration from ffprobe and clamp seeks to buffered range

Two fixes for the MSE video player:

1. Set mediaSource.duration from the ffprobe-reported duration on
   sourceopen, so the seek bar shows the correct video length instead
   of NaN/infinite.

2. Use SourceBuffer mode='sequence' for sequential append without
   timestamp gaps. Add a seeking handler that clamps currentTime to
   the buffered range — seeking beyond buffered data snaps back
   instead of freezing the video.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

0 files changed, 0 insertions, 0 deletions