Added new auth-related methods and events to mcp server (#2496)

This PR adds the following:
* A getAuthStatus method on the mcp server. This returns the auth method
currently in use (chatgpt or apikey) or none if the user is not
authenticated. It also returns the "preferred auth method" which
reflects the `preferred_auth_method` value in the config.
* A logout method on the mcp server. If called, it logs out the user and
deletes the `auth.json` file — the same behavior in the cli's `/logout`
command.
* An `authStatusChange` event notification that is sent when the auth
status changes due to successful login or logout operations.
* Logic to pass command-line config overrides to the mcp server at
startup time. This allows use cases like `codex mcp -c
preferred_auth_method=apikey`.

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

@@ -3,6 +3,7 @@ use std::sync::atomic::AtomicI64;
 use std::sync::atomic::Ordering;
 
 use codex_core::protocol::Event;
+use codex_protocol::mcp_protocol::ServerNotification;
 use mcp_types::JSONRPC_VERSION;
 use mcp_types::JSONRPCError;
 use mcp_types::JSONRPCErrorError;
@@ -121,6 +122,17 @@ impl OutgoingMessageSender {
         .await;
     }
 
+    pub(crate) async fn send_server_notification(&self, notification: ServerNotification) {
+        let method = format!("codex/event/{}", notification);
+        let params = match serde_json::to_value(&notification) {
+            Ok(serde_json::Value::Object(mut map)) => map.remove("data"),
+            _ => None,
+        };
+        let outgoing_message =
+            OutgoingMessage::Notification(OutgoingNotification { method, params });
+        let _ = self.sender.send(outgoing_message).await;
+    }
+
     pub(crate) async fn send_notification(&self, notification: OutgoingNotification) {
         let outgoing_message = OutgoingMessage::Notification(notification);
         let _ = self.sender.send(outgoing_message).await;