Release v0.4.0: Simplify format detection using file extensions - Refactored format detection to use file extensions (.lrcx, .srt, .vtt, .lrc) instead of complex runtime checks - Added is_lyrics_format() helper function for consistent format checking - Fixed SRT/WEBVTT lyrics not clearing during instrumental breaks - Simplified karaoke mode detection from 24 lines to 1 line - Reduced code complexity by 20 lines (43 deletions, 23 insertions)