JSON Response Normalizer

An API response often contains more data than your program needs. Normalize the response into a smaller list of published article summaries.

1. `getPublishedArticles(response)` should return only articles where `status` is `"published"`.
2. `toArticleSummary(article)` should return an object with `id`, `title`, `authorName`, and `views`.
3. `normalizeArticles(response)` should return summaries for published articles only.