Video files (MP4, MKV, etc.) are now processed with ffmpeg to extract
audio to a temp WAV file before loading into wavesurfer. This prevents
the WebView crash caused by trying to fetch multi-GB files into memory.
- New extract_audio Tauri command uses ffmpeg (sidecar-bundled or system)
- Frontend detects video extensions and extracts audio automatically
- User-friendly error if ffmpeg is not installed with install instructions
- Reverted wavesurfer MediaElement approach in favor of clean extraction
- Added FFmpeg install guide to USER_GUIDE.md
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>