- Fixed Windows ffmpeg.exe popups by adding //go:build tags and exporting CreateCommand/CreateCommandRaw properly
- Use utils.GetFFmpegPath(), GetFFprobePath(), GetFFplayPath() instead of hardcoded strings
- Switch AV1 codec to H.264 for better performance (AV1/libsvtav1 is extremely slow)
- Minor UI component refinements (padding, SetMinSize)