feat(consul): deploy HashiCorp Consul 1.22.7 via Helm chart 1.9.7

5-replica server cluster (bootstrapExpect=5) with datacenter=au-syd1,
connect enabled, raft_multiplier=10, http=8500, grpc=8502, https=-1.
10Gi cephrbd-fast-delete PVC. Gateway API HTTPRoute on 443→consul-consul-ui:80→8500.
PDB patched from policy/v1beta1 to policy/v1 for k8s 1.25+.
ArgoCD platform ApplicationSet updated to include consul overlay path.

apps/base/consul/namespace.yaml

@@ -0,0 +1,5 @@
+---
+apiVersion: v1
+kind: Namespace
+metadata:
+  name: consul