core: type platform api key timestamps

crates/crank-core/src/access.rs

@@ -84,8 +84,10 @@ pub struct PlatformApiKey {
     pub prefix: String,
     pub scopes: Vec<PlatformApiKeyScope>,
     pub status: PlatformApiKeyStatus,
-    pub created_at: String,
-    pub last_used_at: Option<String>,
+    #[serde(with = "time::serde::rfc3339")]
+    pub created_at: OffsetDateTime,
+    #[serde(with = "time::serde::rfc3339::option")]
+    pub last_used_at: Option<OffsetDateTime>,
 }
 
 #[cfg(test)]
@@ -93,8 +95,8 @@ mod tests {
     use serde_json::json;
     use time::{OffsetDateTime, format_description::well_known::Rfc3339};
 
-    use super::{User, UserStatus};
-    use crate::ids::UserId;
+    use super::{PlatformApiKey, PlatformApiKeyScope, PlatformApiKeyStatus, User, UserStatus};
+    use crate::ids::{PlatformApiKeyId, UserId, WorkspaceId};
 
     #[test]
     fn user_serializes_created_at_as_rfc3339() {
@@ -127,4 +129,23 @@ mod tests {
             OffsetDateTime::parse("2026-03-25T12:00:00Z", &Rfc3339).unwrap()
         );
     }
+
+    #[test]
+    fn platform_api_key_serializes_timestamps_as_rfc3339() {
+        let api_key = PlatformApiKey {
+            id: PlatformApiKeyId::new("pk_01"),
+            workspace_id: WorkspaceId::new("ws_01"),
+            name: "Primary".to_owned(),
+            prefix: "crk_live".to_owned(),
+            scopes: vec![PlatformApiKeyScope::Read, PlatformApiKeyScope::Write],
+            status: PlatformApiKeyStatus::Active,
+            created_at: OffsetDateTime::parse("2026-03-25T12:01:00Z", &Rfc3339).unwrap(),
+            last_used_at: Some(OffsetDateTime::parse("2026-03-25T12:05:00Z", &Rfc3339).unwrap()),
+        };
+
+        let value = serde_json::to_value(&api_key).unwrap();
+
+        assert_eq!(value["created_at"], json!("2026-03-25T12:01:00Z"));
+        assert_eq!(value["last_used_at"], json!("2026-03-25T12:05:00Z"));
+    }
 }