refactor(server::{useragent::auth, client::auth}): use random based + timestamp nonce instead of monotonic counter in database

server/crates/arbiter-server/src/grpc/client/auth.rs

@@ -44,10 +44,14 @@ impl<'a> AuthTransportAdapter<'a> {
 
     fn response_to_proto(response: auth::Outbound) -> AuthResponsePayload {
         match response {
-            auth::Outbound::AuthChallenge { pubkey, nonce } => {
+            auth::Outbound::AuthChallenge {  challenge } => {
                 AuthResponsePayload::Challenge(ProtoAuthChallenge {
-                    pubkey: pubkey.to_bytes(),
-                    nonce,
+                    timestamp_nanos: challenge
+                        .timestamp
+                        .timestamp_nanos_opt()
+                        .expect("timestamp within range")
+                        as u64,
+                    random: challenge.nonce.to_vec(),
                 })
             }
             auth::Outbound::AuthSuccess => {