Fix ASX trading integration test failures (factor_screen.py fixture mismatch)

Codebase health audit found 8 failed tests including fixture mismatch in factor_screen.py. Fix the integration tests by aligning fixtures with current signal_engine implementation. Acceptance criteria: all integration tests pass, pytest returns clean result.

Note (2026-06-28T10:08:37Z)

Returning to queued — no ASX trading codebase found on filesystem. Blocked until repo is available. Mode C: switching to audit cycle for other projects.