Set a user agent suffix when used as a mcp server (#3395)

This automatically adds a user agent suffix whenever the CLI is used as
a MCP server

codex-rs/core/src/mcp_connection_manager.rs

@@ -17,7 +17,7 @@ use anyhow::Result;
 use anyhow::anyhow;
 use codex_mcp_client::McpClient;
 use mcp_types::ClientCapabilities;
-use mcp_types::Implementation;
+use mcp_types::McpClientInfo;
 use mcp_types::Tool;
 
 use serde_json::json;
@@ -159,7 +159,7 @@ impl McpConnectionManager {
                                 // indicates this should be an empty object.
                                 elicitation: Some(json!({})),
                             },
-                            client_info: Implementation {
+                            client_info: McpClientInfo {
                                 name: "codex-mcp-client".to_owned(),
                                 version: env!("CARGO_PKG_VERSION").to_owned(),
                                 title: Some("Codex".into()),