## Changes
- Add DELETE /api/v1/auth/users/:userId endpoint (admin + superadmin)
- Add deleteUserById service method with role hierarchy enforcement
- Superadmins can remove admins and regular users
- Admins can only remove regular users
- No one can remove superadmins, demo users, or themselves via this endpoint
- Add "Remove user" button with confirmation dialog on edit user page
- Allow admins to view user details and access the edit user page
- Add i18n strings for remove user button and confirmation dialog
## Access control
- superadmin -> can remove admin, user
- admin -> can remove user only
- admin cannot remove superadmin or other admins (enforced on both backend and frontend)