Enhance documentation and address specification gaming in ChargebackOps

fix(eval): sequential per-checkpoint base load + product-grade docs

feat: Implement wait_for_updates action for handling delayed cases and evidence

feat: enhance completion parsing to handle truncated JSON and `<think>` blocks

feat: add per-family evaluation and plotting for training curves

feat: tighten EscalationROI, add ambiguous medium case, LLM note judge wrapper

feat: Add training curve evaluation and plotting utilities with unit tests

Add training notebook and benchmark runner for ChargebackOps

refactor: tighten rubric discrimination + LLM path + add running doc

refactor: update difficulty levels and enhance scoring rubrics in documentation and code

Refactor evidence building and improve code readability in iso_adapter.py