CVE-2026-34067: nimiq-transaction: Panic via `HistoryTreeProof` length mismatch

HistoryTreeProof::verify panics on a malformed proof where history.len() != positions.len() due to assert_eq!(history.len(), positions.len()).

The proof object is derived from untrusted p2p responses (ResponseTransactionsProof.proof) and is therefore attacker-controlled at the network boundary until validated. A malicious peer could trigger a crash by returning a crafted inclusion proof with a length mismatch.