feat(consul): address PR review feedback

- Fix consul HTTPRoute backend: consul-consul-ui -> consul-ui
- Add consul.service.consul hostname to Gateway (cert SAN) and HTTPRoute
- Add consul-svc listener on 443 for consul.service.consul SNI routing
- Convert PDB inline patch to patches/consul-server-pdb.yaml
- Set server.disruptionBudget.maxUnavailable: 1 explicitly in values
- Expose consul DNS service as LoadBalancer (purelb 198.18.200.5) for anycast
- Remove sandbox overlay (not needed in production GitOps)

apps/overlays/au-syd1/consul/patches/consul-server-pdb.yaml

@@ -0,0 +1,3 @@
+- op: replace
+  path: /apiVersion
+  value: policy/v1