fix(gateways): add explicit group/kind/weight to all HTTPRoute refs

ArgoCD diffs against live state where k8s defaults these fields in:
- parentRefs: group=gateway.networking.k8s.io, kind=Gateway
- backendRefs: group="", kind=Service, weight=1

Matches the pattern from #153 (certificateRefs).

apps/base/kanidm/httproute.yaml

@@ -13,7 +13,9 @@ spec:
     - auth.unkin.net
     - au.auth.unkin.net
   parentRefs:
-    - name: kanidm
+    - group: gateway.networking.k8s.io
+      kind: Gateway
+      name: kanidm
       sectionName: http
   rules:
     - filters: