serializeState() {
        return JSON.stringify(this.exportState());
    }
Serializes the current state to a JSON string.

@returns {string} A JSON string representing the current state.

@description
This is a convenience method that exports the state and converts it to a JSON string.

@example
const jsonState = undoRedoManager.serializeState();
// Developer can now save jsonState to file, localStorage, etc.