chore: nuke chat/completions API (#10157)

codex-rs/protocol/src/models.rs

@@ -109,7 +109,7 @@ pub enum ResponseItem {
         encrypted_content: Option<String>,
     },
     LocalShellCall {
-        /// Set when using the chat completions API.
+        /// Legacy id field retained for compatibility with older payloads.
         #[serde(default, skip_serializing)]
         #[ts(skip)]
         id: Option<String>,
@@ -125,8 +125,7 @@ pub enum ResponseItem {
         name: String,
         // The Responses API returns the function call arguments as a *string* that contains
         // JSON, not as an already‑parsed object. We keep it as a raw string here and let
-        // Session::handle_function_call parse it into a Value. This exactly matches the
-        // Chat Completions + Responses API behavior.
+        // Session::handle_function_call parse it into a Value.
         arguments: String,
         call_id: String,
     },
@@ -786,8 +785,7 @@ pub enum FunctionCallOutputContentItem {
 /// `content` preserves the historical plain-string payload so downstream
 /// integrations (tests, logging, etc.) can keep treating tool output as
 /// `String`. When an MCP server returns richer data we additionally populate
-/// `content_items` with the structured form that the Responses/Chat
-/// Completions APIs understand.
+/// `content_items` with the structured form that the Responses API understands.
 #[derive(Debug, Default, Clone, PartialEq, JsonSchema, TS)]
 pub struct FunctionCallOutputPayload {
     pub content: String,