Redesign DemoSection with additional layout, content adjustments, and new demos

- Added User Dashboard demo with `UserCircle` icon and "NEW" badge.
- Introduced "View Complete Demo Tour" CTA linking to the Demo Tour page.
- Adjusted grid layout to support 4 columns for better spacing: `md:grid-cols-2 lg:grid-cols-4`.
- Enhanced Demo credentials modal with richer content outlining user and admin account capabilities.
- Adjusted navigation links: renamed "Components" to "Design System" and added Demo Tour link.
- Updated Demo Tour with leisurely paths, feature checklists, and new demo categories (user and admin flows).

frontend/src/app/dev/page.tsx

@@ -13,8 +13,8 @@ import { Badge } from '@/components/ui/badge';
 import { Separator } from '@/components/ui/separator';
 
 export const metadata: Metadata = {
-  title: 'Design System Hub | Dev',
-  description: 'Interactive demonstrations and documentation for the FastNext design system',
+  title: 'Design System Hub | FastNext Template',
+  description: 'Interactive design system demonstrations with live examples - explore components, layouts, spacing, and forms built with shadcn/ui and Tailwind CSS',
 };
 
 const demoPages = [