Add internationalization (i18n) with next-intl and Italian translations

- Integrated `next-intl` for server-side and client-side i18n support.
- Added English (`en.json`) and Italian (`it.json`) localization files.
- Configured routing with locale-based subdirectories (`/[locale]/path`) using `next-intl`.
- Introduced type-safe i18n utilities and TypeScript definitions for translation keys.
- Updated middleware to handle locale detection and routing.
- Implemented dynamic translation loading to reduce bundle size.
- Enhanced developer experience with auto-complete and compile-time validation for i18n keys.

frontend/next.config.ts

@@ -1,4 +1,8 @@
 import type { NextConfig } from 'next';
+import createNextIntlPlugin from 'next-intl/plugin';
+
+// Initialize next-intl plugin with i18n request config path
+const withNextIntl = createNextIntlPlugin('./src/i18n/request.ts');
 
 const nextConfig: NextConfig = {
   output: 'standalone',
@@ -21,4 +25,5 @@ const nextConfig: NextConfig = {
   // Note: swcMinify is default in Next.js 15
 };
 
-export default nextConfig;
+// Wrap config with next-intl plugin
+export default withNextIntl(nextConfig);