Library generation failed (d706482)

See [failed job](https://github.com/googleapis/google-cloudevents-java/actions/runs/18366249990)

Start with the linked failed job for run 18366249990 and identify which library-generation step failed. Read the failure output and the related repository configuration before determining the affected entry point. Done means the generation job completes successfully without introducing new failures.

索引モデルが issue の本文から書いたものです。