Fix OpenIE fixture guard dependencies

[SonAIengine]

Summary

• install the embedding extra in the OpenIE Fixture Guard so aiohttp-backed preflight contract tests pass on GitHub runners
• document the first remote dispatch failure mode and the dependency fix

Validation

• git diff --check
• uv run ruff format --check src/synaptic eval/scripts tests
• uv run ruff check src/synaptic eval/scripts tests
• uv run pytest tests/test_openie_mz_poc.py -q
• inspected failed run 28556389633 logs: fixture smoke passed; contract tests failed due missing aiohttp