[codex] Add crypto artifact manifest contract

[Pigbibi]

Summary

• add profile-aware artifact_manifest.json generation for the crypto leader live-pool artifact family
• require and publish the artifact manifest through release validation, GCS layout, Firestore payloads, and release-status summaries
• document the upstream/downstream contract and add regression coverage for manifest consistency and checksum validation

Validation

• .venv/bin/python -m unittest tests.test_release_contract tests.test_build_live_pool_smoke tests.test_release_status_summary -v
• .venv/bin/python -m compileall src scripts tests
• python3 -m ruff check .
• git diff --check