Verifies that an on-chain transaction actually settled on a supported chain by querying the chain RPC directly (no balance tracking, no simulation). Submit the onChainTx hash and network; the verifier returns confirmation status, block number, and confirmations. Optionally supply ledgerTxId, from, to, amount, and asset and the verifier compares them against the unshielded entry it finds, setting matchesLedger. This is a public read and needs no authentication.