external
Ed25519 external-signer adapter for out-of-process Ed25519 signing.
The kit injects this adapter into the manager exposed as OZSmartAccountKit.externalSigners, backing the adapter custody model for SelectedSigner.Ed25519 signers (hardware wallet, HSM, or remote signing service). It is the symmetric sibling of externalWallet for the Ed25519 signer kind.
When null, SelectedSigner.Ed25519 signers resolve only against in-memory keypairs registered at runtime via OZExternalSignerManager.addEd25519FromRawKey.