Function verify_row 

pub fn verify_row(
    layout: &RegistryLayout,
    row: &[Word],
    expected_root: Word,
    mismatch_hint: &str,
) -> Vec<Vec<Word>>

Hash a checked-in node row upward and authenticate it against the registry root.

Returns the node pyramid, pyramid[d] holding the 2^d nodes at depth d for d in 0..=row_depth. The row itself is therefore not trust-bearing: a wrong or stale row fails here rather than producing paths that fail opaquely later. mismatch_hint is appended to the panic message so a caller can say how to regenerate its own constants.