Test: Add connector management epic readiness guard

[smithaldon1]

Summary

Closes #206.

• Add an epic-level regression test that maps Epic: Protocol connection management and operator console #206 acceptance criteria onto the implemented connector-management surfaces.
• Verify OPC-UA, MQTT, and BACnet connection profile fixtures validate through the shared contract.
• Verify browser serialization redacts secret/certificate reference values and read-only test-connection failures stay structured/redacted.
• Verify operator-console protocol pages, read-only adapters, normalized event emission, and safety docs remain present.
• Add the required learning-log close-out entry for the connector-management epic.

Test Evidence

• .venv/bin/python -m pytest services/simulator/tests/test_connection_management_epic_readiness.py -> 5 passed
• make test -> 282 passed
• make lint -> All checks passed!
• make typecheck -> compileall packages services passed
• cd apps/web && npm test -> 18 passed
• cd apps/web && npm run lint -> passed
• cd apps/web && npm run typecheck -> passed
• make docs -> Docs are Markdown-only in the MVP skeleton; no docs checker is configured yet.
• git diff --check -> passed

Docs Impact

• Updates docs/LEARNING_LOG.md with the Epic: Protocol connection management and operator console #206 close-out summary.
• No new user-facing feature docs were needed; the safety and local fixture docs were merged in Docs: Document connector safety model #244.

Follow-up Work

• Keep future connector changes aligned with the read-only safety model.
• Future write paths, if any, should start with a separate ADR and governed-action design rather than extending this epic silently.

[smithaldon1]

Reviewed and approved for merge