Replace dataset with cleaned v2: 371 → 300 rows. Dropped unanswerable, page-reference, page-count, and missing-md questions. Source-of-truth for the 0/2/2 + random K-sweep context-degradation experiment.

data/train-00000-of-00001.parquet

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
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-size 37250
+oid sha256:699b3a20b21e6c5fde5dfdf5b86d5f349a1ca355d6636f6833e56672e5cf6b26
+size 32074