feat: add UI components and utilities

- Introduced Skeleton component for loading states.
- Added Slider component with customizable properties.
- Implemented Sonner for toast notifications with icons.
- Created Spinner component for loading indicators.
- Developed Switch component for toggle functionality.
- Added Table component with subcomponents for structured data display.
- Implemented Tabs component for tabbed navigation.
- Created Textarea component for multi-line text input.
- Developed ToggleGroup and Toggle components for grouped toggle functionality.
- Added Tooltip component for contextual hints.
- Implemented useIsMobile hook for responsive design.
- Updated global styles with Tailwind CSS and custom properties.
- Added utility functions for class name management.
- Configured TypeScript paths for easier imports.
- Updated Vite configuration to include Tailwind CSS and path aliases.

libertas-frontend/src/components/ui/spinner.tsx

@@ -0,0 +1,16 @@
+import { Loader2Icon } from "lucide-react"
+
+import { cn } from "@/lib/utils"
+
+function Spinner({ className, ...props }: React.ComponentProps<"svg">) {
+  return (
+    <Loader2Icon
+      role="status"
+      aria-label="Loading"
+      className={cn("size-4 animate-spin", className)}
+      {...props}
+    />
+  )
+}
+
+export { Spinner }