attacklm-dataset v0.6.0 — 20-gram fuzzy decontamination
Implements MAI-Thinking-1 §2.3.1 + §2.4.3 20-gram fuzzy dedup methodology. New scripts/decontam.py with MinHash LSH. Ships 3 eval-set fixtures under data/eval_sets/. Default behavior: report-only (no deletions); --quarantine-output writes matched records to a separate file for review. 551 tests pass.