Add portfolio documentation, demo script, and CI workflow#2

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Copilot wants to merge 3 commits intomainfrom

copilot/portfoliodocs-arrowhead

Commits on Nov 29, 2025

Initial plan
Copilot
committed
Add portfolio documentation, demo, smoke tests, and CI workflow

Copilot
and
edgarbc
committed
Address code review: use proper numpy import, add pytest fixture, add workflow permissions

Copilot
and
edgarbc
committed