Surface custom repo title in settings list, settings nav title, and repo detail view
Extracts the per-leaf @Shared(.repositorySettings(rootURL))
subscription used by the sidebar header into a reusable
`RepoDisplayName` view, then applies it to the settings repository
list and `RepositoryDetailView`. The settings detail's
`.navigationTitle` needs a `String`, so a thin
`RepositorySettingsDetailContainer` wrapper holds the @Shared
subscription and resolves the title.
Hot-path readers (Shelf spine, Canvas card title, toolbar
notification groups) are left on `repository.name` for now — those
methods rebuild a fresh @Shared wrapper per call per frame and
trigger a write/notify storm through the global settings file.
A safe fix needs a single shared subscription threaded through
those methods rather than per-call wrappers.