add linked sshsigchain v2 core

crates/geth-keychain/src/lib.rs

@@ -15,6 +15,17 @@
 //! create their own profile with `KeychainProfile::for_application` or
 //! `KeychainProfile::new` so signed payload namespaces do not overlap.
 
+mod sshsigchain;
+
+pub use sshsigchain::{
+    ChainId as SshSigchainChainId, Digest as SshSigchainDigest, KEYCHAIN_V2_PAYLOAD_VERSION,
+    KEYCHAIN_V2_PROFILE, KeychainV2Policy, KeychainV2State, KeychainV2Verification,
+    SSH_SIGCHAIN_NAMESPACE, SSH_SIGCHAIN_VERSION, SshSigchainError, SshSigchainPolicy,
+    SshSigchainRecord, SshSigchainTrust, SshSigchainVerification, SshSigchainVerifier,
+    decode_keychain_v2_payload, keychain_v2_payload, keychain_v2_unsigned_record,
+    verify_keychain_v2_sigchain, verify_sshsigchain,
+};
+
 use geth_types::{
     AgentId, AuthOpId, Capability, DeviceId, KeyId, NodeId, ResourceId, UnixMillis, UserId,
 };