Delete unused ResponseItem::Message.end_turn (#19605)

This field is unused. Delete it.

codex-rs/protocol/src/items.rs

@@ -266,7 +266,6 @@ pub fn build_hook_prompt_message(fragments: &[HookPromptFragment]) -> Option<Res
         id: Some(uuid::Uuid::new_v4().to_string()),
         role: "user".to_string(),
         content,
-        end_turn: None,
         phase: None,
     })
 }

codex-rs/protocol/src/models.rs

@@ -757,10 +757,6 @@ pub enum ResponseItem {
         id: Option<String>,
         role: String,
         content: Vec<ContentItem>,
-        // Do not use directly, no available consistently across all providers.
-        #[serde(default, skip_serializing_if = "Option::is_none")]
-        #[ts(optional)]
-        end_turn: Option<bool>,
         // Optional output-message phase (for example: "commentary", "final_answer").
         // Availability varies by provider/model, so downstream consumers must
         // preserve fallback behavior when this is absent.
@@ -1114,7 +1110,6 @@ impl From<ResponseInputItem> for ResponseItem {
                 role,
                 content,
                 id: None,
-                end_turn: None,
                 phase: None,
             },
             ResponseInputItem::FunctionCallOutput { call_id, output } => {

codex-rs/protocol/src/protocol.rs

@@ -2867,7 +2867,6 @@ impl From<CompactedItem> for ResponseItem {
             content: vec![ContentItem::OutputText {
                 text: value.message,
             }],
-            end_turn: None,
             phase: None,
         }
     }