[codex] Support generated US equity strategy onboarding

[Pigbibi]

Summary

• Tighten platform eligibility so strategy supported_platforms is respected alongside capability matching.
• Add US equity onboarding docs for generated runtime adapters and PR/tag release order.
• Update live switch and platform matrix docs for the seven live US equity profiles, including dynamic_mega_leveraged_pullback.

Validation

• PYTHONPATH=/home/ubuntu/Projects/QuantPlatformKit/src uv run --with pytest --with pandas --with numpy --with requests --with google-cloud-secret-manager --with google-cloud-storage --with google-auth --with ib-insync --with longport --with schwab-py --with python-binance python -m pytest /home/ubuntu/Projects/QuantPlatformKit/tests -q
• Result: 103 passed, 18 warnings
• git diff --check