Create an MCP endpoint that returns all namespaces with workloads that are part of the Istio mesh.
Detection should rely on injected sidecars (istio-proxy), existing Istio resources (DestinationRule, VirtualService, Sidecar), or metrics from the control plane.
This API will allow clients such as Kiali or other dashboards to quickly discover active mesh namespaces.

Deliverables:

• New /namespaces endpoint.

• Logic to identify namespaces via injected workloads or Istio CRDs.

• Unit tests and integration validation.