feat: add created_at field to CreatedApiKeyResponse and update related handlers

crates/api-types/src/responses.rs

@@ -105,6 +105,7 @@ pub struct ErrorResponse {
 pub struct CreatedApiKeyResponse {
     pub id: Uuid,
     pub name: String,
+    pub created_at: DateTime<Utc>,
     /// Raw API key — shown only once at creation
     pub key: String,
 }

crates/presentation/src/handlers/api_keys.rs

@@ -42,6 +42,7 @@ pub async fn post_api_key(
     Ok(Json(CreatedApiKeyResponse {
         id: key.id.as_uuid(),
         name: key.name,
+        created_at: key.created_at,
         key: raw,
     }))
 }