Administrator escalation via unchecked user registration

Improper authorization in Peppermint Ticket Management 0.4.6 allows remote authenticated users to create administrator accounts. The POST /api/v1/auth/user/register endpoint creates the requested administrator account even when it returns 401 because authorization is enforced only in the client-side interface. A regular account and its bearer token are required; the new account grants persistent administrative access to users, tickets, and system functions.