GitHub repository slug and git ref selector syntax now has one owner:
fabro-types::repository defines GitHubRepositorySlug with a try_new
constructor and the is_valid_github_ref_selector predicate.
fabro-automation keeps its public type path as a re-export of the same
type and delegates its existing parser and ref validation to the shared
grammar, preserving its exact error variants and messages. Server
checkout and materialization code imports the type from its canonical
owner. No wire, API, or behavior change.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
