[codex] Declare crypto artifact contract

[Pigbibi]

Summary

• declare an explicit StrategyArtifactContract for crypto_leader_rotation
• document the crypto platform/strategy split, artifact ownership, and new-strategy checklist requirements
• bump crypto-strategies package version to 0.4.4 for the downstream Binance dependency update

Validation

• PYTHONPATH=src:/home/ubuntu/Projects/QuantPlatformKit/src /home/ubuntu/Projects/UsEquityStrategies/.venv/bin/python -m unittest tests.test_contract_governance tests.test_catalog tests.test_entrypoints -v
• python3 -m compileall src tests
• python3 -m ruff check .
• git diff --check

Follow-up

After this merges, tag v0.4.4 before merging the BinancePlatform dependency bump.