Validate optional AIGuard alignment context

[hyeokjun32]

Summary

• refresh the Runtime Intelligence chain AIGuard handoff-alignment fixture with optional handoff context fields
• make the Lab CI artifact gate validate optional_aiguard_evidence_types as read-only context, not required evidence
• extend smoke and CI template tests plus docs for the optional AIGuard alignment boundary

Tests

• python -m pytest tests/test_runtime_intelligence_smoke_script.py -q -p no:cacheprovider
• python -m pytest tests/test_runtime_intelligence_bundle_manifest.py tests/test_runtime_intelligence_evidence_chain_smoke.py -q -p no:cacheprovider
• python -m pytest tests/test_runtime_intelligence_ci_template.py -q -p no:cacheprovider
• poetry run python3 -m pytest -q -p no:cacheprovider
• poetry run inferedgelab portfolio-demo-check