Add Gateway API page with diagram - New Gateway-API.md (FR): evolution of Ingress, role-oriented model (GatewayClass/Gateway/Routes/ReferenceGrant), why a successor, L4-L7 protocols, manifest, Ingress vs Gateway API, kubectl commands - New images/gateway-api.svg (3 roles -> GatewayClass/Gateway/HTTPRoute -> Service -> Pods) - Add page to Home and _Sidebar; update AGENTS.md page list