Three admin/index pages (groups/tags/users) — each renders a single
"Wähle X aus der Liste" prompt for the desktop split-view layout.
AuthHeader: brand link href + wordmark.
PersonsEmptyState: empty heading + explanation text.
6 tests across five small files.
Refs #496.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
