Function verify 

pub fn verify<D: Digest<OutputSize = U32>, V: HashTreeRoot, const KEY_BYTES: usize>(
    root: &[u8; 32],
    key: &[u8; KEY_BYTES],
    proof: &RadixProof<V, KEY_BYTES>,
) -> Option<RadixVerdict>

Verify a RadixProof for key against root. Returns the verdict, or None if the proof is malformed or does not reconstruct root.

Hardening (all enforced before accepting): term_depth ≤ KEY_BITS; sibling levels strictly ascending, distinct, and all < term_depth; a DivergingLeaf must carry other_key ≠ key sharing key’s term_depth-bit prefix. The terminal depth is soft-authenticated by the fold (a wrong depth cannot reconstruct root without a collision).