Gitea private reusable workflow disclosure to fork runs

Gitea's collaborative-owner authorization path for reading cross-repository reusable workflows does not exclude fork pull request runs. An approved fork workflow targeting a private repository can read workflow files from another private repository that trusts the base repository's owner through collaborative-owner configuration. The issue exposes private reusable workflow contents at caller-selected Git refs; it does not itself grant write access or code execution in the other repository.