Tailwind CSS 4 Migration (#100)

* Updated to TailwindCSS v4
* Moved CSS module to its own CSS file because of lightingcss strict validation
* Respect next parameter in middleware
* Updated all packages. 
* Split CSSs for better organization.
* Redesigned theme and auth pages
* Improved pill and header design
* Formatted files using Prettier
* Better footer layout
* Better auth layout
* Bump version of the repository to 2.0.0

packages/ui/src/shadcn/calendar.tsx

@@ -26,7 +26,7 @@ function Calendar({
         month: 'space-y-4',
         caption: 'flex justify-center pt-1 relative items-center',
         caption_label: 'text-sm font-medium',
-        nav: 'space-x-1 flex items-center',
+        nav: 'gap-x-2 flex items-center',
         nav_button: cn(
           buttonVariants({ variant: 'outline' }),
           'h-7 w-7 bg-transparent p-0 opacity-50 hover:opacity-100',