In the original sense of the word, vibe coding means neither reading nor caring about the code: https://simonwillison.net/2025/Mar/19/vibe-coding/
Some would use the term "Agent Engineering" for what OP did.
Some would use the term "Agent Engineering" for what OP did.
FWIW I agree with your post and perhaps we need a separate name for people who just instructed an LLM to build something, but then took the trouble to understand how the thing actually works.
It seems to me that this is not the case here. The author used LLM to build the whole thing and left it at that. Which is completely fair, I'd do the same if I just wanted to scratch an itch with the minimal amount of effort, but then I wouldn't go around claiming "I built it".