Add FeedService and integrate into NostrFeed module

- Introduced FeedService to manage feed functionality, including subscription and deduplication of posts.
- Updated NostrFeed module to register FeedService in the DI container and initialize it during installation.
- Refactored useFeed composable to utilize FeedService for managing feed state and loading posts.
- Enhanced NostrFeed component to display posts and handle loading states more effectively.
- Changed Home.vue to use the 'all' feed type for broader content display.

These changes improve the modularity and functionality of the feed system, providing a more robust user experience.

src/core/di-container.ts

@@ -131,7 +131,10 @@ export const SERVICE_TOKENS = {
   
   // Chat services
   CHAT_SERVICE: Symbol('chatService'),
-  
+
+  // Feed services
+  FEED_SERVICE: Symbol('feedService'),
+
   // Events services
   EVENTS_SERVICE: Symbol('eventsService'),