domain: add cross-cutting value objects (SystemId, DateTimeStamp, Checksum, StructuredData)

crates/api-types/src/responses.rs

@@ -5,7 +5,6 @@ use uuid::Uuid;
 pub struct UserResponse {
     pub id: Uuid,
     pub email: String,
-    pub role: String,
     pub created_at: DateTime<Utc>,
 }
 
@@ -20,7 +19,6 @@ impl UserResponse {
         Self {
             id: *user.id.as_uuid(),
             email: user.email.to_string(),
-            role: user.role.to_string(),
             created_at: user.created_at,
         }
     }