Update PR branch with latest upstream

[ShlomoStept]

Goal

Update cleanup/upstream-pr-final with latest upstream/main and keep PR current.

Commands

git checkout cleanup/upstream-pr-final
git fetch upstream
git rebase upstream/main
git push origin cleanup/upstream-pr-final --force-with-lease

Acceptance Criteria

• Branch rebased on current upstream/main
• Tests pass locally (uv run python -m pytest)
• PR reflects latest upstream base