✨ feat: Remove Theme Switcher

- Update body class to use `dark` instead of `light` for dark mode
- Remove `ThemeSwitcher` component as it is no longer needed
- Update global CSS to set dark mode styles on the `.dark` class instead of `.light`

app/globals.css

@@ -18,6 +18,6 @@ body {
   font-family: "JetBrains Mono", monospace;
 }
 
-.light {
+.dark {
   @apply bg-black text-white;
 }