- Introduced `verein-feature` module for managing Vereine, including list, detail, and editor views using `MsMasterDetailLayout`.
- Added new domain models (`Verein`, `VereinStatus`) and integrated mock data for development.
- Registered the new feature in `settings.gradle.kts` and `DesktopMainLayout.kt`, including breadcrumb navigation and entry point.
- Updated `VeranstaltungenUebersichtV2` to add Vereine as a quick-access KPI tile.
- Removed unnecessary logout functionality and adjusted the root navigation for consistency.
Signed-off-by: Stefan Mogeritsch <stefan.mo.co@gmail.com>