feat(puppet): migrate puppetboard Ingress to Gateway API (#130)

## Summary

- Replace `Ingress` (nginx) with `Gateway` + `HTTPRoute` using `traefik-internal` GatewayClass
- TLS terminated at the Gateway listener; cert-manager provisions the certificate via `vault-issuer`
- external-dns annotations moved to the Gateway
- `ingress_puppetdb.yaml` is unchanged in this PR (separate PR)

## Test plan

- [ ] ArgoCD syncs the puppet app cleanly
- [ ] cert-manager issues the `puppetboard-tls` certificate
- [ ] external-dns creates the DNS record
- [ ] `https://puppetboard.k8s.syd1.au.unkin.net` is reachable

Reviewed-on: #130

apps/base/puppet/httproute_puppetboard.yaml

@@ -0,0 +1,25 @@
+---
+apiVersion: gateway.networking.k8s.io/v1
+kind: HTTPRoute
+metadata:
+  labels:
+    app.kubernetes.io/component: puppetboard
+    app.kubernetes.io/instance: puppetserver
+    app.kubernetes.io/name: puppetserver
+    app.kubernetes.io/version: 8.8.0
+  name: puppetboard
+  namespace: puppet
+spec:
+  hostnames:
+    - puppetboard.k8s.syd1.au.unkin.net
+  parentRefs:
+    - name: puppetboard
+      sectionName: https
+  rules:
+    - backendRefs:
+        - name: puppetboard
+          port: 80
+      matches:
+        - path:
+            type: PathPrefix
+            value: /