find_node()

The goal of find_node() is to search through the linked list of nodes and return a pointer to the node with a given name. For example, if your list looks like:

nodeA → nodeB → nodeC → NULL

and you call find_node(node_list, "nodeB"), it will return a pointer to the nodeB structure.
If the name is not found, it returns NULL.

This is a helper function used in many places (e.g., get_link_info(), get_route_info(), etc.).