Support ProxyTerminatingEndpoints KEP

[bleggett]

ProxyTerminatingEndpoint support is an upstream K8S KEP:

https://github.com/kubernetes/enhancements/blob/master/keps/sig-network/1669-proxy-terminating-endpoints/README.md

ztunnel should probably support this, especially as it gets integrated into K8S proper, along with tests.

Preliminary work for this is started with:

• https://github.com/istio/ztunnel/pull/374
• https://github.com/istio/istio/pull/43126 to add a binary workload status to the Workload API

Remaining work after those PRs are merged to support this feature:

• Implement ProxyTerminatingEndpoint logic in ztunnel - e.g. actually use the workload states on the ztunnel side.
• Write tests.

[daixiang0]

what is status now?