feat(api-gateway): 添加 MPC Account Service 路由配置

添加共管钱包 API 路由，将 /api/v1/co-managed/* 请求转发到 account-service (端口 4000)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/api-gateway/kong.yml

@@ -250,6 +250,17 @@ services:
           - /api/v1/balance
         strip_path: false
 
+  # ---------------------------------------------------------------------------
+  # MPC Account Service - MPC 账户服务 (Go - 共管钱包)
+  # ---------------------------------------------------------------------------
+  - name: mpc-account-service
+    url: http://192.168.1.111:4000
+    routes:
+      - name: mpc-co-managed
+        paths:
+          - /api/v1/co-managed
+        strip_path: false
+
 # =============================================================================
 # Plugins - 全局插件配置
 # =============================================================================