Remove stacked class from datacard (see nhanh1_train.csv update)

Remove stacked class: 100% synthetic + 100% recall across all models = trivially separable, unreliable signal

Document Nhanh 2 files (nhanh2_normal.csv, nhanh2_anomalous_eval.csv) in datacard

Add Nhanh 2 held-out anomalous eval set (D3, 25,065 rows)

Add Nhanh 2 (anomaly) benign pool: 91,935 rows

Update license section with verified per-source findings

Add balanced multiclass SQLi dataset (68,159 rows)

Add dataset card

initial commit