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/artifactapi/httproute.yaml

@@ -8,7 +8,9 @@ spec:
   hostnames:
     - artifactapi.k8s.syd1.au.unkin.net
   parentRefs:
-    - name: artifactapi
+    - group: gateway.networking.k8s.io
+      kind: Gateway
+      name: artifactapi
       sectionName: http
   rules:
     - filters:
@@ -30,12 +32,17 @@ spec:
   hostnames:
     - artifactapi.k8s.syd1.au.unkin.net
   parentRefs:
-    - name: artifactapi
+    - group: gateway.networking.k8s.io
+      kind: Gateway
+      name: artifactapi
       sectionName: https
   rules:
     - backendRefs:
-        - name: artifactapi-api
+        - group: ""
+          kind: Service
+          name: artifactapi-api
           port: 80
+          weight: 1
       matches:
         - path:
             type: PathPrefix