adminAuth populates req.admin, not req.user, so currentAdminId was always
undefined in the /api/admin/picpeak/import handler. reinjectCurrentAdmin()
then had no account to preserve and the admin_users table was fully replaced
by the uploaded backup — a crafted .picpeak let any admin with backup.restore
take over every admin account (critical). One-line fix: pass req.admin.id.
Closes GHSA-qxfx-4493-4v8f and its duplicate GHSA-pjp6-jcrj-3cr5.