Keep monthly optimization fanout upstream-only

[Pigbibi]

Summary

• make the monthly optimization planner consume only the CryptoSnapshotPipelines AI review artifact
• stop fanout and experiment-validation dispatches to BinancePlatform
• restrict secondary-review recommended action owners to CryptoSnapshotPipelines and CryptoStrategies
• preserve downstream BinancePlatform impact as review context while keeping downstream runtime fixes incident-first

Verification

• python -m py_compile scripts/build_monthly_optimization_plan.py scripts/fanout_monthly_optimization_tasks.py scripts/post_monthly_optimization_issue.py scripts/run_openai_secondary_review.py scripts/build_ai_review_payload.py scripts/prepare_auto_optimization_pr.py
• python -m unittest tests.test_build_monthly_optimization_plan tests.test_fanout_monthly_optimization_tasks tests.test_monthly_optimization_planner_workflow_config tests.test_post_monthly_optimization_issue tests.test_run_openai_secondary_review tests.test_build_ai_review_payload tests.test_prepare_auto_optimization_pr -v
• python3 -m ruff check .
• git diff --check