Add AdminAuthPipelineTests (WebApplicationFactory + RoleInjectingHandler) to
enforce that ConfigViewer is denied CanPublish-gated pages while FleetAdmin is
permitted, and that an authenticated FleetAdmin session can reach the homepage.
Existing PageAuthorizationTests (anon page rejection) and AuthEndpointsTests
(login cookie + hub auth) cover cases (a)-(c); this file adds case (d).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>