fix: accept raw Ed25519 public keys

[litaibai2046-debug]

Summary

• Accept 32-byte raw Ed25519 public keys in addition to PEM/base64 DER SPKI input.
• Wrap raw keys with the standard Ed25519 SubjectPublicKeyInfo prefix before passing them to Node crypto.
• Update the CLI option help and add a verifier regression fixture/test for raw base64 public keys.

Why

Some key endpoints may expose Ed25519 public keys as raw 32-byte base64 values instead of DER SPKI. The verifier already supports PEM and base64 DER; this makes key resolution tolerant of the raw representation as well.

Verification

• npm test
• npm run build