docs: add LmxFakeProxy to test infrastructure documentation

test_infra.md

@@ -11,6 +11,7 @@ This document describes the local Docker-based test infrastructure for ScadaLink
 | MS SQL 2022 | `mcr.microsoft.com/mssql/server:2022-latest` | 1433 | `infra/mssql/setup.sql` |
 | SMTP (Mailpit) | `axllent/mailpit:latest` | 1025 (SMTP), 8025 (web) | Environment vars |
 | REST API (Flask) | Custom build (`infra/restapi/Dockerfile`) | 5200 | `infra/restapi/app.py` |
+| LmxFakeProxy | Custom build (`infra/lmxfakeproxy/Dockerfile`) | 50051 (gRPC) | Environment vars |
 
 ## Quick Start
 
@@ -40,6 +41,7 @@ Each service has a dedicated document with configuration details, verification s
 - [test_infra_db.md](test_infra_db.md) — MS SQL 2022 database
 - [test_infra_smtp.md](test_infra_smtp.md) — SMTP test server (Mailpit)
 - [test_infra_restapi.md](test_infra_restapi.md) — REST API test server (Flask)
+- [test_infra_lmxfakeproxy.md](test_infra_lmxfakeproxy.md) — LmxProxy fake server (OPC UA bridge)
 
 ## Connection Strings
 
@@ -107,6 +109,7 @@ infra/
   opcua/nodes.json            # Custom OPC UA tag definitions
   restapi/app.py              # Flask REST API server
   restapi/Dockerfile          # REST API container build
+  lmxfakeproxy/              # .NET gRPC proxy bridging LmxProxy protocol to OPC UA
   tools/                      # Python CLI tools (opcua, ldap, mssql, smtp, restapi)
   README.md                   # Quick-start for the infra folder
 ```