Document Lab decision policy rules

[hyeokjun32]

Summary

• Add a reviewer-facing Lab Decision Policy reference for inferedge-lab-decision-policy-v1
• Link the policy from README, README.ko, and pipeline contract docs
• Add a test that keeps documented policy rules aligned with POLICY_RULES

Tests

• poetry run python3 -m pytest -q tests/test_deployment_decision.py tests/test_ci_doc_guards.py
• poetry run inferedgelab core4-conformance-check
• poetry run inferedgelab portfolio-demo-check
• poetry run python3 -m pytest -q
• git diff --check