Extend user-agent authentication to support Ed25519, ECDSA (secp256k1), and RSA (PSS+SHA-256) with minimal protocol and storage changes. Add key_type to auth requests and useragent_client, update key parsing/signature verification paths, and keep backward compatibility by treating UNSPECIFIED as Ed25519.

@@ -0,0 +1,8 @@
+disallowed-methods = [

@@ -24,6 +24,7 @@ async-trait.workspace = true
 
 [build-dependencies]
 tonic-prost-build = "0.14.3"
+protoc-bin-vendored = "3"

@@ -3,6 +3,11 @@ use tonic_prost_build::configure;
 static PROTOBUF_DIR: &str = "../../../protobufs";
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
+    if std::env::var("PROTOC").is_err() {

@@ -199,2 +256,2 @@
-    ) -> Result<VerifyingKey, Self::Error> {
-        Ok(state_data.key)
+    ) -> Result<AuthPublicKey, Self::Error> {
+        // ChallengeContext.key cannot be taken by value because smlang passes it by ref;