fix: improve WP_DEBUG settings restoration

- Fix cleanup function to properly restore original WP_DEBUG settings
- Remove duplicate cleanup checks and redundant variables
- Add proper line spacing when restoring wp-config.php settings
- Add debug logging to track settings restoration
- Fix file paths after moving index.js to main directory
- Ensure cleanup runs on all quit scenarios (menu, window close, quit button)

This ensures the original WordPress debug settings are properly restored
when quitting the app, maintaining proper file formatting and spacing.

Author: jonathanbossenger