feat: add KubeStellar Console to Kubernetes section

[clubanderson]

KubeStellar Console is an open-source multi-cluster Kubernetes dashboard — CNCF Sandbox project with AI-powered operations, 20+ CNCF integrations (Argo, Kyverno, Istio, Prometheus), and real-time observability across edge and cloud.\n\nHappy to adjust description or placement.

[be-next]

Hi @clubanderson, thanks for the contribution and for taking the time to open this PR — it's appreciated!

I took a look at KubeStellar Console and it's a promising project. However, this list is specifically scoped to performance engineering — tools for observability (metrics, tracing, profiling, alerting) and performance testing (load testing, benchmarking, chaos engineering). KubeStellar Console is primarily a multi-cluster Kubernetes management dashboard, which falls a bit outside that focus.

That said, it would be a great fit for awesome-kubernetes — which we already reference in our Related section — or other Kubernetes-focused awesome lists.

If KubeStellar Console develops deeper performance-specific capabilities in the future (e.g., dedicated performance profiling views, latency analysis across clusters, or integration with load testing workflows), I'd be happy to reconsider.

Thanks again for the interest in the list, and keep up the good work on the project!