Refactor and enhance email management functionality
- Replaced jQuery with vanilla JavaScript for email generation, fetching, and management in api.js.
- Implemented localStorage for state management of email and session ID.
- Added error handling and loading states for better user experience.
- Enhanced UI in index.html with new controls for auto-refresh and email search functionality.
- Updated CSS for improved styling, including dark mode support and responsive design adjustments.
- Introduced modal for viewing email content and improved email actions (copy, delete, download attachments).
- Added theme switcher for light/dark mode.
- Changed API Services.