Kong Mesh: the kuma-dp readiness service exposes the Envoy admin API without authentication

When kuma-dp is configured with the Envoy admin API on a Unix domain socket, which is the default, its readiness service on TCP port 9902 - bound to all interfaces - forwards almost the entire Envoy admin API to any caller that can reach the port, with no authentication. An attacker with network access to a data plane's port 9902, for example another pod on the cluster network, can read Envoy and data plane configuration without credentials: config dumps, cluster and listener lists, stats, and the mesh trust bundle. Exposure is read-only - destructive Envoy admin actions are blocked and private keys are not exposed.