docs: cross-reference docker-env2 from root README, CLAUDE.md, and infra README

CLAUDE.md

@@ -9,6 +9,7 @@ When a change is requested, the default assumption is: update the design doc *an
 - `src/` — C#/.NET implementation, one project per component (e.g. `ScadaLink.AuditLog`, `ScadaLink.NotificationOutbox`, `ScadaLink.SiteCallAudit`, `ScadaLink.CentralUI`, `ScadaLink.Host`, …). Solution file: `ScadaLink.slnx`.
 - `tests/` — Test projects (unit + integration).
 - `docker/` — 8-node cluster topology (2 central + 3 sites), `deploy.sh`, per-node `appsettings.*.json`. See [`docker/README.md`](docker/README.md) for setup, ports, and management commands. Rebuild + redeploy with `bash docker/deploy.sh`.
+- `docker-env2/` — Minimal second cluster topology (2 central + 1 site × 2 nodes), runs concurrently with `docker/` on host ports 91XX. Built specifically for testing the Transport (#24) feature with two real environments. See [`docker-env2/README.md`](docker-env2/README.md). Rebuild + redeploy with `bash docker-env2/deploy.sh`.
 - `infra/` — Docker Compose for local test services (LDAP, MS SQL, OPC UA, SMTP, REST API, Traefik).
 - `README.md` — Master index with component table and architecture diagrams.
 - `docs/requirements/HighLevelReqs.md` — Complete high-level requirements covering all functional areas.

README.md

@@ -25,6 +25,15 @@ This document serves as the master index for the SCADA system design. The system
 - Central cluster: 2-node active/standby behind a load balancer.
 - Site clusters: 2-node active/standby, headless (no UI).
 
+## Local Test Environments
+
+Two Docker-based cluster topologies are available for local development and testing:
+
+- **Primary** ([`docker/`](docker/)) — Full topology (2 central + 3 sites × 2 nodes + Traefik). Default development target.
+- **Env2** ([`docker-env2/`](docker-env2/)) — Minimal sibling stack (2 central + 1 site × 2 nodes + Traefik), runs concurrently with primary on host ports 91XX. Purpose: exercise the Transport (#24) bundle export/import feature against a real second environment.
+
+Both stacks share the infrastructure services in [`infra/`](infra/) (MS SQL, LDAP, SMTP, OPC UA, REST API).
+
 ## Document Map
 
 ### Requirements

infra/README.md

@@ -37,6 +37,16 @@ docker exec -i scadalink-mssql /opt/mssql-tools18/bin/sqlcmd \
   -i /docker-entrypoint-initdb.d/machinedata_seed.sql
 ```
 
+For the second environment (`docker-env2/`), also apply the env2 database setup:
+
+```bash
+docker exec -i scadalink-mssql /opt/mssql-tools18/bin/sqlcmd \
+  -S localhost -U sa -P 'ScadaLink_Dev1#' -C \
+  -i /docker-entrypoint-initdb.d/setup-env2.sql
+```
+
+This creates `ScadaLinkConfig2` and `ScadaLinkMachineData2` databases on the same MSSQL instance. The script is also invoked automatically by `docker-env2/deploy.sh` via `docker-env2/init-db.sh`, so manual application here is only needed if you want the databases ready before first env2 deploy.
+
 ## Stopping & Teardown
 
 **Stop containers** (data persists in SQL volume):