fix(mpc-service): connect to mpc-system network

- Changed MPC URLs from 192.168.1.111 to Docker internal names
- Added mpc-system_mpc-network to mpc-service for cross-network communication

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

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

backend/services/docker-compose.yml

@@ -334,12 +334,12 @@ services:
       - KAFKA_BROKERS=kafka:29092
       - KAFKA_CLIENT_ID=mpc-service
       - KAFKA_GROUP_ID=mpc-service-group
-      # MPC System (deployed on 192.168.1.111)
-      - MPC_ACCOUNT_SERVICE_URL=http://192.168.1.111:4000
-      - MPC_COORDINATOR_URL=http://192.168.1.111:8081
-      - MPC_SESSION_COORDINATOR_URL=http://192.168.1.111:8081
-      - MPC_MESSAGE_ROUTER_WS_URL=ws://192.168.1.111:8082
-      - MPC_SERVER_PARTY_API_URL=http://192.168.1.111:8083
+      # MPC System - 使用 Docker 网络内部地址
+      - MPC_ACCOUNT_SERVICE_URL=http://mpc-account-service:8080
+      - MPC_COORDINATOR_URL=http://mpc-session-coordinator:8080
+      - MPC_SESSION_COORDINATOR_URL=http://mpc-session-coordinator:8080
+      - MPC_MESSAGE_ROUTER_WS_URL=ws://mpc-message-router:8080
+      - MPC_SERVER_PARTY_API_URL=http://mpc-server-party-api:8080
       - MPC_API_KEY=rwa-mpc-api-key-2024-secure-access-token
       - SHARE_MASTER_KEY=${SHARE_MASTER_KEY}
     depends_on:
@@ -358,6 +358,7 @@ services:
     restart: unless-stopped
     networks:
       - rwa-network
+      - mpc-system_mpc-network
 
   leaderboard-service:
     build:
@@ -592,3 +593,5 @@ volumes:
 networks:
   rwa-network:
     driver: bridge
+  mpc-system_mpc-network:
+    external: true