core: type auth profile timestamps

crates/crank-core/src/operation.rs

@@ -264,6 +264,7 @@ mod tests {
     use std::collections::BTreeMap;
 
     use serde_json::json;
+    use time::{OffsetDateTime, format_description::well_known::Rfc3339};
 
     use crate::{
         auth::{AuthConfig, AuthProfile, BearerAuthConfig},
@@ -280,6 +281,10 @@ mod tests {
         },
     };
 
+    fn timestamp(value: &str) -> OffsetDateTime {
+        OffsetDateTime::parse(value, &Rfc3339).unwrap()
+    }
+
     #[test]
     fn rest_target_serializes_with_kind_tag() {
         let target = Target::Rest(RestTarget {
@@ -440,8 +445,8 @@ mod tests {
                 header_name: "Authorization".to_owned(),
                 secret_id: crate::ids::SecretId::new("secret_crm_prod_token"),
             }),
-            created_at: "2026-03-25T08:00:00Z".to_owned(),
-            updated_at: "2026-03-25T08:00:00Z".to_owned(),
+            created_at: timestamp("2026-03-25T08:00:00Z"),
+            updated_at: timestamp("2026-03-25T08:00:00Z"),
         };
 
         let value = serde_json::to_value(profile).unwrap();