fix: remove traefik-dashboard IngressRoute (conflicts with k3s built-in Traefik Helm chart)

The built-in k3s Traefik Helm chart creates its own traefik-dashboard
IngressRoute. Our ArgoCD-managed copy blocked Helm install because
Helm requires ownership labels (app.kubernetes.io/managed-by=Helm).

Removing our copy lets the built-in chart manage the dashboard route.

bootstrap/traefik-routes/manifests/traefik-dashboard.yaml

@@ -1,19 +0,0 @@
-# Traefik Dashboard IngressRoute
-apiVersion: traefik.io/v1alpha1
-kind: IngressRoute
-metadata:
-  name: traefik-dashboard
-  namespace: kube-system
-spec:
-  entryPoints:
-    - websecure
-  routes:
-    - match: HostRegexp(`traefik.k3s\..+\.local`) && (PathPrefix(`/dashboard`) || PathPrefix(`/api`))
-      kind: Rule
-      middlewares:
-        - name: sslheader
-          namespace: kube-system
-      services:
-        - name: api@internal
-          kind: TraefikService
-  tls: {}