presentation wiring

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

crates/adapters/auth/Cargo.toml

@@ -4,3 +4,5 @@ version = "0.1.0"
 edition = "2024"
 
 [dependencies]
+async-trait = { workspace = true }
+domain = { workspace = true }

crates/adapters/auth/src/lib.rs

@@ -1,14 +1,13 @@
-pub fn add(left: u64, right: u64) -> u64 {
-    left + right
-}
+use async_trait::async_trait;
+use domain::{errors::DomainError, ports::AuthService, value_objects::UserId};
 
-#[cfg(test)]
-mod tests {
-    use super::*;
+pub struct StubAuthService;
 
-    #[test]
-    fn it_works() {
-        let result = add(2, 2);
-        assert_eq!(result, 4);
+#[async_trait]
+impl AuthService for StubAuthService {
+    async fn validate_token(&self, _token: &str) -> Result<UserId, DomainError> {
+        Err(DomainError::InfrastructureError(
+            "auth service not implemented".into(),
+        ))
     }
 }