Add audio file detection by magic numbers
# Add audio file detection by magic numbers

## Changes
- Add `is_audio_file()` function to detect audio files by checking file headers
- Support WAV, FLAC, MP3, M4A/AAC formats
- Replace extension-based detection with content-based detection in `read_and_config_file()`

## Why
More reliable audio file detection without relying on file extensions

## Test
- Tested with various audio formats (WAV, MP3)