feat(gateway): expose gatewayAPI.gateway.infrastructure passthrough (#939)

Render Gateway spec.infrastructure (labels/annotations) so Gateway API
controllers propagate the metadata onto the provisioned Service/Deployment,
e.g. AWS internal NLB annotations. Purely additive: guarded by `with`, so
the default {} renders no change.

- spire-lib: toYaml passthrough in the shared Gateway helper
- spire, spire-nested: add the values param; regenerate READMEs
- tests/unit: cover the positive passthrough case

Signed-off-by: sabsari <[email protected]>
Co-authored-by: Claude Opus 4.8 <[email protected]>

charts/spire-lib/templates/_helpers.tpl

@@ -589,6 +589,10 @@ metadata:
   {{- end }}
 spec:
   gatewayClassName: {{ required "gatewayAPI.gateway.className is required to render the shared Gateway" $obj.className | quote }}
+  {{- with $obj.infrastructure }}
+  infrastructure:
+    {{- toYaml . | nindent 4 }}
+  {{- end }}
   allowedListeners:
     namespaces:
       from: {{ default "All" $obj.allowedListenersNamespaces }}