HTTP adapter for the Essentials admin/monitoring SPIs (fenced locks, durable queues, scheduler, event store, CDC, PostgreSQL statistics). Exposes the contract defined by admin-api-spec over Spring WebMVC, delegating to the existing *Api beans. Authentication is the host's concern: the caller's principal is resolved through EssentialsAuthenticatedUser and authorized by role through EssentialsSecurityProvider, both of which the consumer implements.