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/base/traefik-system/gatewayclass-external.yaml

@@ -4,4 +4,4 @@ kind: GatewayClass
 metadata:
   name: traefik-external
 spec:
-  controllerName: traefik.io/gateway-controller
+  controllerName: traefik.io/gateway-controller-external

apps/base/traefik-system/gatewayclass-internal.yaml

@@ -4,4 +4,4 @@ kind: GatewayClass
 metadata:
   name: traefik-internal
 spec:
-  controllerName: traefik.io/gateway-controller
+  controllerName: traefik.io/gateway-controller-internal