Remove all obsolete authentication, settings, admin, and demo-related components and pages

- Eliminated redundant components, pages, and layouts related to authentication (`login`, `register`, `password-reset`, etc.), user settings, admin, and demos.
- Simplified the frontend structure by removing unused dynamic imports, forms, and test code.
- Refactored configurations and metadata imports to exclude references to removed features.
- Streamlined the project for future development and improved maintainability by discarding legacy and unused code.

frontend/src/components/layout/Footer.tsx

@@ -5,7 +5,7 @@
 
 'use client';
 
-import Link from 'next/link';
+import { Link } from '@/lib/i18n/routing';
 
 export function Footer() {
   const currentYear = new Date().getFullYear();