SIENTIAPDE-1973: Implement per-connector OPC client certificates and remove legacy read engine.
This update overhauls certificate management, transitioning from a single platform certificate to individual client certificates defined in the slot configuration. The CertProvider now downloads certificates from MinIO based on certificate_id, applying dynamic security policies (mode, policy) from the slot. The legacy READ_ENGINE=legacy option and OpcManager have been entirely removed, standardizing on the ServerReader with strict slot v2 enforcement. Write command resolution (ServerConfigResolver) now consistently uses connectors joined with opc_certificates. The CERT_BUCKET environment variable is no longer used.
GatewayRuntime builds and owns the F4 object graph (CertProvider/pool ->
WriteEngine/NatsWriteConsumer -> ActiveReadEngine -> optional GrpcServer),
reusing the existing ingestor's logger/notification_handler/metrics_controller
and DataManager (CertProvider shares its Mongo connection instead of opening
a second one). app.py starts it after prepare_ingestor, sweeps idle OPC
connections each loop iteration, and stops it on shutdown. A NATS connect
failure at startup is logged/notified but never crashes the app -- the read
path keeps working and idle_sweep() retries the consumer start.
ingestor.py needed no changes: data_manager is already reachable via
ingestor.ingestor_manager.data_manager.
Also documents the new MinIO/Postgres env vars this wiring reads (via
sientia_do's build_postgres_config for Postgres) in .env.example, and
updates test_app.py's fixture to mock GatewayConfig/GatewayRuntime so the
existing app tests keep exercising only what they mocked before.
Remove deprecated files and enhance documentation
- Deleted `coverage.sh`, `docker-compose.yaml`, `Dockerfile`, and simulator-related files to streamline the project structure.
- Updated `README.md` to provide a comprehensive overview of the OPC Ingestor, including features, architecture, installation, usage, and troubleshooting.
- Enhanced docstrings across various classes and methods in the `ingestor` module for better clarity and maintainability.
- Improved Prometheus metrics documentation in `metrics.py` to ensure proper monitoring and observability of the system.
