Add Fullscreen Button and Keyboard Shortcut

[dnafication]

Enhance the Talk Timer application by adding a fullscreen button or a keyboard shortcut to toggle fullscreen mode. This feature will improve the user experience by allowing users to focus solely on the timer without any distractions.

Tasks:

• Add Fullscreen Button: Implement a button in the UI that toggles fullscreen mode. Place the button in a visible and accessible location on the interface.
• Implement Keyboard Shortcut: Add a keyboard shortcut (e.g., F key) to toggle fullscreen mode. Ensure the shortcut works across different browsers and devices.
• Update Documentation:Update the README.md file to include instructions on how to use the fullscreen feature. Mention the keyboard shortcut in the documentation.

[Vidhanvyrs]

hi @dnafication I would be happy to work on this issue. If possible can you please assign it to me so i can straightaway start the implementation