feat: add UI components and improve layout

- Introduced new UI components: Input, Label, ScrollArea, Separator, Sheet, Skeleton, Table.
- Implemented utility function for class name merging.
- Enhanced the authenticated layout with a sidebar and user menu.
- Added login functionality with improved UI and error handling.
- Integrated theme provider for consistent theming across the application.
- Updated styles with Tailwind CSS and custom properties for dark mode support.
- Refactored routes to utilize new components and improve user experience.

src/lib/utils.ts

@@ -0,0 +1,6 @@
+import { clsx, type ClassValue } from "clsx"
+import { twMerge } from "tailwind-merge"
+
+export function cn(...inputs: ClassValue[]) {
+  return twMerge(clsx(inputs))
+}