v0.10.0

Add HDF5 named-feature dataset support: a dataset whose last axis has named columns via an attribute (a <dataset-name>_features convention, checked on the dataset itself or its parent group) is now split into individually selectable/plottable columns instead of being flattened into one meaningless combined histogram. Detection is conservative -- only applied when a candidate attribute's length exactly matches the dataset's last axis -- so files without this convention are completely unaffected. Reported and verified against a real physics dataset with a (9764, 7) 'jet' dataset holding 7 distinct named quantities.