feat(notifications): add real-time notification system

Add database tables for notifications and WebSocket tickets
Implement REST API and WebSocket server for real-time delivery
Add NotificationBell component with dropdown and unread badge
Trigger alerts for comments, reactions, and AI moderation results

backend/src/queries.ts

@@ -16,6 +16,7 @@ import {
   requestAiModerationReview,
   type AiModerationStatus
 } from './aiModeration.ts';
+import { createLifePostReactionNotification } from './notifications.ts';
 
 type QueryValue = string | string[] | undefined;
 
@@ -3989,6 +3990,10 @@ export async function setLifePostReaction(
     [postId, userId, reactionType]
   );
 
+  if (result) {
+    await createLifePostReactionNotification(result.postId, userId);
+  }
+
   return result ? getLifePostById(result.postId, userId, locale) : null;
 }