{{/* Resolve a possibly-$ref'd OpenAPI node against the spec root.

  Input dict:
  api  — the unmarshaled spec root (plain map from transform.Unmarshal)
  node — the node to resolve; may be a map, slice, primitive, or nil

  Returns:
  - if node is a map containing a "$ref" key, returns the target node
  reached by walking the JSON-Pointer fragment (only internal "#/" refs
  are supported)
  - otherwise returns node unchanged
*/}}
{{- $node := .node -}}
{{- if reflect.IsMap $node -}}
  {{- with index $node "$ref" -}}
    {{- if hasPrefix . "#/" -}}
      {{- $parts := after 1 (split . "/") -}}
      {{- $cur := $.api -}}
      {{- range $parts -}}
        {{- $cur = index $cur . -}}
      {{- end -}}
      {{- $node = $cur -}}
    {{- end -}}
  {{- end -}}
{{- end -}}
{{- return $node -}}