Tidy cross_judge_case03.py for ruff lint compliance (#8)

Wraps long lines and reorders imports so 'ruff check' is clean across
src/ tests/ validation/. No behavior change.

The already-committed partial run artifacts (opus succeeded, gpt5 quota'd,
gemini key missing) remain valid evidence and continue to load through
the existing test_cross_judge.py fixtures (23 tests still pass).

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>