Exodus-compatible Ed25519 import and on-chain transaction signing

[roccomuso]

Adds support for importing 64-character hex private keys produced by wallets that use BIP32 + Ed25519 on the same Ontology path as OWallet (e.g. Exodus), and fixes Ed25519 transaction signing so signatures match what the network verifies.

Problem

Import: Default import treats 64-hex keys as ECDSA P-256, so addresses did not match Exodus even when the derivation path matched on paper.
Decrypt: Encrypted keystores for EDDSA / Ed25519 must be wrapped with algorithm + parameters from the saved JSON; using only the ciphertext string breaks decryption.
Send: After import, txs failed with “transaction verify signature fail” because ontology-ts-sdk applied an extra SHA512 step before Ed25519 signing, while the chain verifies Ed25519 over the raw transaction hash (getSignContent() / double-SHA256 payload).

Test

1. Import a known Exodus 64-hex key with the new option enabled → address and balances match Exodus.
2. Send ONT / ONG (and an OEP-4 if you use one) → tx confirms; no signature error.
3. Regression: create/import a normal ECDSA wallet → send still works.