Refactor backend configuration and enhance news fetching functionality

- Introduced a Config dataclass in config.py to manage API keys, RSS feeds, and directory paths more effectively.
- Updated the NewsFetcher class to include retry logic for fetching articles from RSS feeds.
- Modified the EmbeddingGenerator and NewsRecommender classes to utilize the new configuration structure.
- Enhanced main.py to implement API token verification for secure access to news fetching and recommendations.

backend/templates/home.html

@@ -15,7 +15,7 @@
             <div class="p-6">
                 <h2 class="text-2xl font-semibold text-gray-800 mb-4">Latest News</h2>
                 <p class="text-gray-600 mb-6">View the latest news articles fetched from our RSS feeds.</p>
-                <a href="/fetch-news" class="inline-block bg-blue-600 text-white px-6 py-3 rounded-md font-medium hover:bg-blue-700 transition-colors duration-300">
+                <a href="/fetch-news?token=default_secret_token" class="inline-block bg-blue-600 text-white px-6 py-3 rounded-md font-medium hover:bg-blue-700 transition-colors duration-300">
                     View Latest News
                 </a>
             </div>
@@ -27,7 +27,7 @@
                 <h2 class="text-2xl font-semibold text-gray-800 mb-4">News Recommendations</h2>
                 <p class="text-gray-600 mb-6">Get personalized news recommendations based on your interests.</p>
                 <div class="space-y-4">
-                    <a href="/recommend-news?query=technology" class="block bg-blue-600 text-white px-6 py-3 rounded-md font-medium hover:bg-blue-700 transition-colors duration-300 text-center">
+                    <a href="/recommend-news?query=technology?token=default_secret_token" class="block bg-blue-600 text-white px-6 py-3 rounded-md font-medium hover:bg-blue-700 transition-colors duration-300 text-center">
                         Technology News
                     </a>
                     <a href="/recommend-news?query=artificial intelligence" class="block bg-blue-600 text-white px-6 py-3 rounded-md font-medium hover:bg-blue-700 transition-colors duration-300 text-center">