remove mcp-server/src/mcp_protocol.rs and the code that depends on it (#2360)

codex-rs/mcp-server/src/lib.rs

@@ -18,15 +18,12 @@ use tracing_subscriber::EnvFilter;
 mod codex_message_processor;
 mod codex_tool_config;
 mod codex_tool_runner;
-mod conversation_loop;
 mod error_code;
 mod exec_approval;
 mod json_to_toml;
-pub mod mcp_protocol;
 pub(crate) mod message_processor;
 mod outgoing_message;
 mod patch_approval;
-pub(crate) mod tool_handlers;
 pub mod wire_format;
 
 use crate::message_processor::MessageProcessor;