fix(ws): only process unread notifications and handle multiple payload formats

Previously, the notification handler would process all notifications regardless of read status, and only accepted `extra_data` from the payload. Now it:
- Only calls systemNotificationService and increments unread count for unread notifications
- Falls back to `payload.extra` or `payload.data` when `extra_data` is not present

src/services/core/wsService.ts

@@ -619,12 +619,14 @@ class WebSocketService {
       receiver_id: payload.receiver_id,
       category: payload.category,
       system_type: payload.system_type,
-      extra_data: payload.extra_data,
+      extra_data: payload.extra_data || payload.extra || payload.data,
       is_read: !!payload.is_read,
       created_at: payload.created_at || new Date().toISOString(),
     };
     this.emit('notification', m);
-    systemNotificationService.handleWSMessage(m as any).catch(() => {});
+    if (!m.is_read) {
+      systemNotificationService.handleWSMessage(m as any).catch(() => {});
+    }
   }
 
   // Call signaling handlers

src/stores/message/services/WSMessageHandler.ts

@@ -131,9 +131,10 @@ export class WSMessageHandler implements IWSMessageHandler {
 
     // 监听系统通知，实时更新系统未读数
     wsService.on('notification', (message: WSNotificationMessage) => {
-      if (!message.is_read) {
+      if (message.is_read) {
-        this.incrementSystemUnread();
+        return;
       }
+      this.incrementSystemUnread();
       if (message.created_at) {
         const store = useMessageStore.getState();
         const currentLast = store.lastSystemMessageAt;