- Refactor EmbedM4AMetadata to use streaming instead of loading entire file
- Use os.Open + ReadAt instead of os.ReadFile for memory efficiency
- Atomic file replacement via temp file + rename for safer writes
- New helper functions: findAtomInRange, readAtomHeaderAt, copyRange, buildUdtaAtom
- Refactor GetM4AQuality to use streaming with findAudioSampleEntry
- Use NewHTTPClientWithTimeout helper in lyrics.go, qobuz.go, tidal.go
- Update CHANGELOG with performance improvements and MP3 metadata support