fix(traefik): set controllerName on GatewayClasses and Traefik providers (#135)

## Problem

Both GatewayClasses (`traefik-internal`, `traefik-external`) were stuck as `Unknown`. Neither Traefik deployment had `controllerName` set in `kubernetesGateway`, so both defaulted to `traefik.io/gateway-controller` — which matched neither GatewayClass.

## Fix

- `gatewayclass-internal.yaml`: `controllerName: traefik.io/gateway-controller-internal`
- `gatewayclass-external.yaml`: `controllerName: traefik.io/gateway-controller-external`
- `values-internal.yaml`: added `controllerName: traefik.io/gateway-controller-internal`
- `values-external.yaml`: added `controllerName: traefik.io/gateway-controller-external`

## Test plan

- [ ] ArgoCD syncs traefik-system cleanly
- [ ] `kubectl get gatewayclass` shows both as `Accepted: True`

Reviewed-on: #135

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

@@ -29,6 +29,9 @@ providers:
     nativeLBByDefault: false
     labelSelector: "traefik.io/instance=external"
 
+additionalArguments:
+  - "--providers.kubernetesgateway.controllerName=traefik.io/gateway-controller-external"
+
 logs:
   access:
     enabled: true

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

@@ -29,6 +29,9 @@ providers:
     nativeLBByDefault: false
     labelSelector: "traefik.io/instance=internal"
 
+additionalArguments:
+  - "--providers.kubernetesgateway.controllerName=traefik.io/gateway-controller-internal"
+
 logs:
   access:
     enabled: true