- rebuild PHP minifier UI with responsive design and dark mode support

- implement enhanced minification algorithm with separate comment and whitespace options
- add file upload/download functionality with drag and drop support
- introduce local storage for auto-saving code
- add toast notification system for user feedback
- implement keyboard shortcuts (Ctrl+Enter to minify, Ctrl+S to download)
- add line numbers toggle option for the code editor
- improve stats display with formatted byte sizes

Author: TobiasMue91