Remove Responses V1 websocket implementation (#13364)

V2 is the way to go!

codex-rs/codex-api/src/common.rs

@@ -67,8 +67,6 @@ pub enum ResponseEvent {
     Completed {
         response_id: String,
         token_usage: Option<TokenUsage>,
-        /// Whether the client can append more items to a long-running websocket response.
-        can_append: bool,
     },
     OutputTextDelta(String),
     ReasoningSummaryDelta {
@@ -211,20 +209,12 @@ pub struct ResponseCreateWsRequest {
     pub client_metadata: Option<HashMap<String, String>>,
 }
 
-#[derive(Debug, Serialize)]
-pub struct ResponseAppendWsRequest {
-    pub input: Vec<ResponseItem>,
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub client_metadata: Option<HashMap<String, String>>,
-}
 #[derive(Debug, Serialize)]
 #[serde(tag = "type")]
 #[allow(clippy::large_enum_variant)]
 pub enum ResponsesWsRequest {
     #[serde(rename = "response.create")]
     ResponseCreate(ResponseCreateWsRequest),
-    #[serde(rename = "response.append")]
-    ResponseAppend(ResponseAppendWsRequest),
 }
 
 pub fn create_text_param_for_request(