The previous Admin-006 commit added <AntiforgeryToken /> to the logout form
and updated the comment on the endpoint, but did not update LogoutAsync to
actually call IAntiforgery.ValidateRequestAsync. Blazor's UseAntiforgery()
middleware does not automatically validate minimal-API endpoints, so a
tokenless POST still succeeded. This commit injects IAntiforgery into the
handler, wraps ValidateRequestAsync in a try/catch, and returns 400 on
AntiforgeryValidationException. The endpoint keeps .DisableAntiforgery() to
prevent the middleware from also trying to read the body (which would cause
a double-read). The regression test is updated to log in first (to get an
authenticated session) before asserting 400 on a tokenless logout POST.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
a0aa4a4819