Remove CI configuration and VSCode extensions; refactor CommandPalette and Header components

Commit notes

- Deleted the CI workflow configuration file to streamline the project setup. - Removed the VSCode extensions recommendations file to reduce clutter. - Refactored the CommandPalette component by removing the 'Go to Home' navigation command. - Updated the Header component to simplify the navigation links and improve accessibility with aria-labels for buttons.

These changes enhance the project's maintainability and user interface consistency.