Fix broken factor_screen.py pytest tests (8 failures)

Project plan task 15b5e71e — fix the broken factor_screen.py test fixtures causing 8 pytest failures in asx-trading project.

Note (2026-06-28T17:43:30Z)

Picked up by ralph at 2026-06-28T17:42 BNE. Plan: diagnose factor_screen.py test failures, then fix them. First step: look at the failing tests and understand root cause.