The model to traverse
Callback called for each node in the tree. The visitor can: - Return false to stop the traversal completely - Return {skipChildren: true} to skip processing children - Return {delete: true} to remove the current node from its parent - Return nothing or true to continue normally The visitor receives the current node and its parent (null for top-level nodes).
Walks an IJsonModel tree using a stack-based approach, calling visitor for each node. The walk processes borders first, then traverses the main layout in a depth-first manner.