Refactor Pomodoro Timer: Enhance task management and UI updates

- Updated WORKSHOP_GUIDE.md to reflect changes in the Pomodoro timer structure and task management.
- Removed unused timer.js and taskManager.js files to streamline the codebase.
- Consolidated timer logic and task management into main.js, improving clarity and functionality.
- Enhanced HTML structure in pomodoro.html for better task input and display.
- Implemented task addition, editing, and deletion features with dynamic rendering.
- Improved UI updates for timer display and mode switching.

Author: geraldsberongoy