Support end_turn flag (#9698)

Experimental flag that signals the end of the turn.

codex-rs/codex-api/src/endpoint/chat.rs

@@ -193,6 +193,7 @@ impl Stream for AggregatedStream {
                             content: vec![ContentItem::OutputText {
                                 text: std::mem::take(&mut this.cumulative),
                             }],
+                            end_turn: None,
                         };
                         this.pending
                             .push_back(ResponseEvent::OutputItemDone(aggregated_message));

codex-rs/codex-api/src/requests/chat.rs

@@ -386,6 +386,7 @@ mod tests {
             content: vec![ContentItem::InputText {
                 text: "hi".to_string(),
             }],
+            end_turn: None,
         }];
         let req = ChatRequestBuilder::new("gpt-test", "inst", &prompt_input, &[])
             .conversation_id(Some("conv-1".into()))
@@ -412,6 +413,7 @@ mod tests {
                 content: vec![ContentItem::InputText {
                     text: "read these".to_string(),
                 }],
+                end_turn: None,
             },
             ResponseItem::FunctionCall {
                 id: None,

codex-rs/codex-api/src/requests/responses.rs

@@ -223,11 +223,13 @@ mod tests {
                 id: Some("m1".into()),
                 role: "assistant".into(),
                 content: Vec::new(),
+                end_turn: None,
             },
             ResponseItem::Message {
                 id: None,
                 role: "assistant".into(),
                 content: Vec::new(),
+                end_turn: None,
             },
         ];
 

codex-rs/codex-api/src/sse/chat.rs

@@ -330,6 +330,7 @@ async fn append_assistant_text(
             id: None,
             role: "assistant".to_string(),
             content: vec![],
+            end_turn: None,
         };
         *assistant_item = Some(item.clone());
         let _ = tx_event

codex-rs/codex-api/tests/clients.rs

@@ -308,6 +308,7 @@ async fn streaming_client_retries_on_transport_error() -> Result<()> {
             content: vec![ContentItem::InputText {
                 text: "hi".to_string(),
             }],
+            end_turn: None,
         }],
         tools: Vec::<Value>::new(),
         parallel_tool_calls: false,