Add Theme Toggling with Ant Design CSS and LocalStorage Persistence

[smdbs01]

What's Done

Serve both light and dark Ant Design CSS files from the public folder. Implement theme toggling using JoseRFelix/react-css-theme-switcher, with user preferences stored in localStorage for basic persistence.

This PR fixes issue #6.

Noteworthy Changes

1. Dependency Updates in package.json:
   • Updated antd: The original lock file indicated version 4.24.1 was installed, suggesting that the ^5.17.0 specifier was an unintended change.
   • Adjusted @types/styled-components: Restricted to <=5.1.32 as versions 5.1.33+ introduced breaking changes (see StackOverflow).

Future Improvements

1. Dark Mode Support for Custom Components:
   • Added a dark class to the html tag when Dark Mode is preferred. Non-Ant Design components can now adopt the dark theme using CSS variables by defining values in :root and :root.dark.
2. SVG Refactor:
   • The sun and moon SVGs should be moved to a separate directory for better organization and reusability.