feat(AIC-3534): add a TypeSafe Jev judge handler

[andrewklatzke]

Summary

• Add launchdarkly-ai-typesafe, a judge handler that sends a variation's classifiers to Jev in one call.
• Each label becomes its own judge_results entry, tracked on that label's eventKey, with the selected label as the reason.
• A score is the expected rubric index divided by one less than the number of levels, then clamped to 0–1.

https://launchdarkly.atlassian.net/browse/AIC-3534

Test plan

• pytest packages/typesafe/tests packages/client/tests/test_judges.py packages/client/tests/test_conversation.py packages/client/tests/test_judge_scoring.py packages/client/tests/test_schema.py
• Run a TypeSafe judge variation and confirm one result per label, with the label value in response

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