fix: add missing except block and __main__ guard in export_audio.py (closes #83)

[botbikamordehai2-sketch]

What

The main() function in export_audio.py opens a try block that calls audio_export() but the file ends without a corresponding except/finally block. This incomplete try statement causes a SyntaxError when Python parses the file, making the script completely non-functional.

Additionally, the if __name__ == '__main__' guard and main() invocation are missing, meaning the script cannot be run directly.

Fix

• Added the missing except Exception block with proper error handling using the already-imported traceback and sys modules
• Added sys.exit(1) on error and the if __name__ == '__main__': main() guard

Closes #83