Add Dockerized OPC UA demo simulator

[smithaldon1]

Summary

Closes #188.

• Adds a read-only Dockerized OPC UA demo simulator service for the manufacturer demo.
• Exposes a small simulator-backed namespace for one site, one line, Filler F-201, Checkweigher CW-201, required process tags, and demo state tags.
• Starts the server in normal mode with scenario=fill_weight_drift_demo and drift_active=false.
• Logs demo-only safety framing, endpoint, namespace, scenario, drift state, and exposed node details at startup.
• Documents the endpoint, startup command, tag list, and demo-only safety boundary.

Test Evidence

• .venv/bin/python -m pytest services/simulator/tests/test_opcua_demo_server.py services/simulator/tests/test_opc_ua_demo_namespace_docs.py - 8 passed
• make test - 203 passed
• make lint - All checks passed
• make typecheck - compileall completed successfully
• make docs - Markdown-only docs target completed
• docker compose -f infra/docker/docker-compose.yml config - passed
• git diff --check - passed
• git diff --cached --check - passed

Docker runtime note:

• docker compose -f infra/docker/docker-compose.yml up --build -d opcua-simulator could not be completed in this environment because the Docker daemon/socket is unavailable: failed to connect to the docker API at unix:///Users/aldonsmith/.docker/run/docker.sock.
• docker version shows the Docker client is installed, but the daemon connection fails with the same socket error.
• The local asyncua server/client test does verify the endpoint implementation and normal-mode tag reads outside Docker.

Docs Impact

• Updated services/simulator/README.md with the Docker Compose command, endpoint URL, tag list, state tags, and demo-only framing.
• Updated docs/demo/OPC_UA_DEMO_NAMESPACE.md with line_speed and demo state tags.
• Updated docs/demo/MANUFACTURER_DEMO_RUNBOOK.md to point to the simulator README for the OPC UA service command and tag list.
• Updated docs/LEARNING_LOG.md with the learning summary.

Follow-up Work

• Run the Compose service on a machine with Docker Desktop/daemon running to verify container startup logs end-to-end.
• Add a future ingestion adapter or smoke test against this read-only demo endpoint in a separate issue.

[smithaldon1]

Reviewed and approved for merge