[codex-analytics] add protocol-native turn timestamps

codex-rs/exec/src/lib.rs

@@ -717,6 +717,7 @@ async fn run_exec_session(args: ExecRunArgs) -> anyhow::Result<()> {
                 TurnStartedNotification {
                     thread_id: response.review_thread_id.clone(),
                     turn: response.turn.clone(),
+                    created_at: 0,
                 },
             ));
             let task_id = response.turn.id;