feat(infra): add second OPC UA server instance (opcua2) on port 50010

Enables multi-server testing with independent state. Both instances
share the same nodes.json tag config. Updated all infra documentation.

infra/README.md

@@ -8,11 +8,12 @@ Local Docker-based test services for ScadaLink development.
 docker compose up -d
 ```
 
-This starts five services:
+This starts the following services:
 
 | Service | Port | Purpose |
 |---------|------|---------|
 | OPC UA (Azure IoT OPC PLC) | 50000 (OPC UA), 8080 (web) | Simulated OPC UA server with ScadaLink-style tags |
+| OPC UA 2 (Azure IoT OPC PLC) | 50010 (OPC UA), 8081 (web) | Second OPC UA server instance (same tags, independent state) |
 | LDAP (GLAuth) | 3893 | Lightweight LDAP with test users/groups matching ScadaLink roles |
 | MS SQL 2022 | 1433 | Configuration and machine data databases |
 | SMTP (Mailpit) | 1025 (SMTP), 8025 (web) | Email capture for notification testing |
@@ -46,7 +47,7 @@ docker compose down
 
 **Stop a single service** (leave the others running):
 ```bash
-docker compose stop opcua      # or: ldap, mssql, smtp, restapi
+docker compose stop opcua      # or: opcua2, ldap, mssql, smtp, restapi
 docker compose start opcua     # bring it back without recreating
 ```
 

infra/docker-compose.yml

@@ -20,6 +20,27 @@ services:
       - scadalink-net
     restart: unless-stopped
 
+  opcua2:
+    image: mcr.microsoft.com/iotedge/opc-plc:latest
+    container_name: scadalink-opcua2
+    ports:
+      - "50010:50010"
+      - "8081:8080"
+    volumes:
+      - ./opcua/nodes.json:/app/config/nodes.json:ro
+    command: >
+      --autoaccept
+      --unsecuretransport
+      --sph
+      --sn=5 --sr=10 --st=uint
+      --fn=5 --fr=1 --ft=uint
+      --gn=5
+      --nf=/app/config/nodes.json
+      --pn=50010
+    networks:
+      - scadalink-net
+    restart: unless-stopped
+
   ldap:
     image: glauth/glauth:latest
     container_name: scadalink-ldap