Function verify_detached 

pub fn verify_detached(
    bytes: &[u8],
    signature_b64: &str,
    public_key_b64: &str,
) -> Result<(), BundleError>

Verify a detached ed25519 signature over raw bytes against a base64-encoded 32-byte public key and base64-encoded 64-byte signature. Used to authenticate documents that aren’t manifests (e.g. the refreshable model catalog in car-inference): the source signs the exact file bytes, so no canonicalization is needed.