Arize Dataset

Handles dataset operations for Arize's evaluation and experimentation workflow. You can create datasets from CSV, JSON, JSONL, or Parquet files, append new examples, export everything back out, and manage versions. The CLI is `ax datasets`, and it works across spaces with name or ID lookups. One nice touch: you can pipe data directly via stdin instead of saving temp files, and there's an auto-escalation rule that catches truncated exports at 500 rows and reruns with the unlimited flag. Useful when you're building test sets, managing golden datasets, or need to version your eval data alongside experiments.