Set traefik-external externalTrafficPolicy to Local (#519)

With the default Cluster external policy, kube-proxy SNATs inbound traffic to the traefik-external LoadBalancer, hiding real client IPs from traefik and adding a cross-node hop. Local preserves source IPs. Internal policy stays Cluster so in-cluster callers on nodes without a traefik-external pod still reach it.

- Set `externalTrafficPolicy: Local` on the traefik-external Service
- Set `internalTrafficPolicy: Cluster` explicitly

Reviewed-on: #519
Co-authored-by: unkin-agent <unkin-agent@unkin.net>
Co-committed-by: unkin-agent <unkin-agent@unkin.net>

apps/overlays/au-syd1/traefik-system/values-external.yaml

@@ -59,6 +59,8 @@ service:
   spec:
     type: LoadBalancer
     loadBalancerIP: "198.18.199.0"
+    externalTrafficPolicy: Local
+    internalTrafficPolicy: Cluster
   additionalServices: {}
 
 autoscaling: