feat(kong): 添加 referral-service 路由 /api/v1/referral

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/kong/kong.yml

@@ -70,6 +70,15 @@ services:
           - /api/v1/admin/versions
         strip_path: false
 
+  # --- referral-service (NestJS :3013) ---
+  - name: referral-service
+    url: http://referral-service:3013
+    routes:
+      - name: referral-routes
+        paths:
+          - /api/v1/referral
+        strip_path: false
+
   # --- issuer-service (NestJS :3002) ---
   - name: issuer-service
     url: http://issuer-service:3002