Allow --output-last-message to print to stdout

codex-rs/exec/src/event_processor_noop.rs

@@ -0,0 +1,18 @@
+use codex_core::protocol::Event;
+use codex_core::protocol::EventMsg;
+
+use crate::event_processor::CodexStatus;
+use crate::event_processor::EventProcessor;
+
+pub(crate) struct EventProcessorNoop {}
+
+impl EventProcessor for EventProcessorNoop {
+    fn process_event(&mut self, event: Event) -> CodexStatus {
+        let Event { id: _, msg } = event;
+        match msg {
+            EventMsg::ShutdownComplete => CodexStatus::Shutdown,
+            EventMsg::TaskComplete(_) => CodexStatus::InitiateShutdown,
+            _ => CodexStatus::Running,
+        }
+    }
+}