feat: migrate purelb to ArgoCD

Migrate PureLB load balancer from Terragrunt to ArgoCD/Kustomize.
Deploys purelb v0.13.0 with two LBNodeAgent and two ServiceGroup CRs
(common: 198.18.200.0/24, dmz: 198.18.199.0/24).
Adds LBNodeAgent and ServiceGroup to kubeconform skip list (no CRD catalog schema).

💘 Generated with Crush

Assisted-by: Claude Sonnet 4.6 via Crush <crush@charm.land>

apps/base/purelb/lbnodeagents.yaml

@@ -0,0 +1,28 @@
+---
+apiVersion: purelb.io/v1
+kind: LBNodeAgent
+metadata:
+  labels:
+    app.kubernetes.io/component: lbnodeagent
+    app.kubernetes.io/name: purelb
+  name: common
+  namespace: purelb
+spec:
+  local:
+    extlbint: kube-lb0
+    localint: default
+    sendgarp: false
+---
+apiVersion: purelb.io/v1
+kind: LBNodeAgent
+metadata:
+  labels:
+    app.kubernetes.io/component: lbnodeagent
+    app.kubernetes.io/name: purelb
+  name: dmz
+  namespace: purelb
+spec:
+  local:
+    extlbint: kube-lb0
+    localint: default
+    sendgarp: false