Add warning logs for missing emitters and failed event delivery in EventPublisher

backend/src/main/java/com/alttd/altitudeweb/services/chat/event_publisher/EventPublisher.java

@@ -95,6 +95,7 @@ public class EventPublisher {
     public void sendToUser(String uniqueKey, String eventName, String json) {
         List<SseEmitter> userEmitters = emitterMap.get(uniqueKey);
         if (userEmitters == null) {
+            log.warn("No emitters found for unique key: {}", uniqueKey);
             return;
         }
 
@@ -102,6 +103,7 @@ public class EventPublisher {
             try {
                 emitter.send(SseEmitter.event().name(eventName).data(json));
             } catch (IOException e) {
+                log.warn("Failed to send event to user: {}", uniqueKey, e);
                 cleanup(emitter);
             }
         }