Add native Jev System One judging with selectable presets

[kargibora]

Summary

• Add Jev as a native OpenRouter System One judge through the existing judge.prompt_preset interface.
• Include typesafe-choice, typesafe-multilingual-choice, typesafe-comparative-score, and typesafe-fluency-choice presets. Preserve native hard verdicts and soft probability distributions, including graded Score and both-order evaluation.
• Integrate with main's inference cache and MT-Bench-101 prompt registry without changing official benchmark judging protocols.

Validation

• uv run pytest -q: 469 passed.
• uv run ruff check . and uv run ruff format --check ..
• Built wheel and verified packaged Jev presets and MT-Bench-101 templates.
• Live Jev System One both-order smoke test completed before the main merge.