fix(luminork): Update set_ai_agent_executed to return a 204 status code

Author: stack72

lib/luminork-server/src/service/v1/user.rs

@@ -75,7 +75,7 @@ impl IntoResponse for UserError {
 )]
 pub async fn set_ai_agent_executed(
     WorkspaceDalContext(ref ctx): WorkspaceDalContext,
-) -> UserResult<()> {
+) -> UserResult<StatusCode> {
     let HistoryActor::User(user_pk) = ctx.history_actor() else {
         return Err(UserError::MissingUser);
     };
@@ -96,5 +96,5 @@ pub async fn set_ai_agent_executed(
 
     ctx.commit().await?;
 
-    Ok(())
+    Ok(StatusCode::NO_CONTENT)
 }