feat: enhance user service with role assignment and frontend scroll-area ref support

- Updated `users.service.ts` to assign user roles dynamically based on RBAC.
- Enhanced JWT generation to include the user's role in `auth.service.ts`.
- Added `viewportRef` prop support to `ScrollArea` component in the frontend for improved flexibility.

frontend/src/components/ui/scroll-area.tsx

@@ -8,8 +8,11 @@ import { cn } from "@/lib/utils";
 function ScrollArea({
 	className,
 	children,
+	viewportRef,
 	...props
-}: React.ComponentProps<typeof ScrollAreaPrimitive.Root>) {
+}: React.ComponentProps<typeof ScrollAreaPrimitive.Root> & {
+	viewportRef?: React.Ref<HTMLDivElement>;
+}) {
 	return (
 		<ScrollAreaPrimitive.Root
 			data-slot="scroll-area"
@@ -18,6 +21,7 @@ function ScrollArea({
 		>
 			<ScrollAreaPrimitive.Viewport
 				data-slot="scroll-area-viewport"
+				ref={viewportRef}
 				className="focus-visible:ring-ring/50 size-full rounded-[inherit] transition-[color,box-shadow] outline-none focus-visible:ring-[3px] focus-visible:outline-1"
 			>
 				{children}