Function create_sshsig 

pub fn create_sshsig(
    seed: &SecureSeed,
    data: &[u8],
    namespace: &str,
) -> Result<String, CryptoError>

Create an SSHSIG signature and return it as a PEM-armored string.

Uses the ssh-key crate to produce a standard SSHSIG signature from an Ed25519 seed and arbitrary data, suitable for Git commit signing.

Args:

• seed: The Ed25519 private key seed.
• data: The raw bytes to sign.
• namespace: The SSHSIG namespace (e.g., “git”).

Usage:

let pem = create_sshsig(&seed, b"commit data", "git")?;
assert!(pem.starts_with("-----BEGIN SSH SIGNATURE-----"));