Exactly one repository is configured with the old names, and it is
migrated by hand in the same move as this release. The fallback is
therefore a transition of days, not a feature anyone reading the release
notes or the configuration reference has to plan around.
Removed from `releases.html` and `docs/configuration.md`. The mechanism
itself is unchanged and stays described where it is worked on: in
`ConfigFiles`, in `StateDirMigration`, and in the migration plan.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
