code-mode: expose transport-neutral session runtime

codex-rs/code-mode-protocol/src/session.rs

@@ -63,9 +63,6 @@ pub trait CodeModeSessionDelegate: Send + Sync {
         text: String,
         cancellation_token: CancellationToken,
     ) -> NotificationFuture<'a>;
-
-    /// Releases delegate state associated with a cell after it reaches a terminal state.
-    fn cell_closed(&self, cell_id: &CellId);
 }
 
 /// A stateful code-mode session owned by one Codex thread.