[Code scan] Convert atom-type arrays to scalars in feature_to_block

[njzjz]

This issue comes from a Codex global repository scan.

Problem

feature_to_block() indexes ase.data.chemical_symbols with the ndarray returned by idp.untransform(...):

dftio/dftio/data/interfaces/ham_to_feature.py

Line 199 in c9d128f

symbol = ase.data.chemical_symbols[idp.untransform(data[_keys.ATOM_TYPE_KEY][atom].reshape(-1))]

The same pattern appears for edge atoms:

dftio/dftio/data/interfaces/ham_to_feature.py

Lines 226 to 227 in c9d128f

	symbol_i = ase.data.chemical_symbols[idp.untransform(data[_keys.ATOM_TYPE_KEY][atom_i].reshape(-1))]
	symbol_j = ase.data.chemical_symbols[idp.untransform(data[_keys.ATOM_TYPE_KEY][atom_j].reshape(-1))]

When atom types are shaped like (N, 1), idp.untransform(data[_keys.ATOM_TYPE_KEY][atom].reshape(-1)) returns an array such as array([14]), and list indexing with that ndarray raises TypeError.

Suggested fix

Convert the untransformed result to a scalar before indexing:

atomic_number = int(np.asarray(idp.untransform(...)).reshape(-1)[0])
symbol = ase.data.chemical_symbols[atomic_number]