feat: Implement user topic subscription

supabase/functions/create-novu-subscriber/index.ts

@@ -203,6 +203,18 @@ serve(async (req) => {
     const duration = endRequest(tracking);
     console.log('Subscriber created successfully:', subscriber.data, { requestId: tracking.requestId, duration });
 
+    // Add subscriber to "users" topic for global announcements
+    try {
+      console.log('Adding subscriber to "users" topic...', { subscriberId });
+      await novu.topics.addSubscribers('users', {
+        subscribers: [subscriberId],
+      });
+      console.log('Successfully added subscriber to "users" topic', { subscriberId });
+    } catch (topicError: any) {
+      // Non-blocking - log error but don't fail the request
+      console.error('Failed to add subscriber to "users" topic:', topicError.message, { subscriberId });
+    }
+
     return new Response(
       JSON.stringify({
         success: true,