envoy-gateway-app release v1.9.0

Changed

• Update Envoy Gateway to v1.8.3.
• Update cert-manager config in the cluster values for all performance test suites.

Added

• Set karpenter.sh/do-not-disrupt: "true" on the Envoy Gateway control-plane pods, so Karpenter does not voluntarily consolidate them. A control-plane reschedule forces the Envoy proxies to reconnect and can leave them wedged with stale/absent TLS secrets over delta xDS until restarted (see envoyproxy/gateway#9519).
• Add perf-report repo-specific claude skill to automatically generate performance test report as html files.