refactor(openapi): remove unused route-group prep state

Simplifies route-group preparation by dropping dead metadata that was no longer used by the OpenAPI builder.

Co-Authored-By: Virgil <virgil@lethean.io>

openapi.go

@@ -37,9 +37,8 @@ type SpecBuilder struct {
 }
 
 type preparedRouteGroup struct {
-	group       RouteGroup
-	descs       []RouteDescription
-	describable bool
+	group RouteGroup
+	descs []RouteDescription
 }
 
 // Build generates the complete OpenAPI 3.1 JSON spec.
@@ -788,11 +787,9 @@ func prepareRouteGroups(groups []RouteGroup) []preparedRouteGroup {
 		if isHiddenRouteGroup(g) {
 			continue
 		}
-		describable := isDescribableRouteGroup(g)
 		out = append(out, preparedRouteGroup{
-			group:       g,
-			descs:       collectRouteDescriptions(g),
-			describable: describable,
+			group: g,
+			descs: collectRouteDescriptions(g),
 		})
 	}
 
@@ -838,16 +835,6 @@ func isHiddenRouteGroup(g RouteGroup) bool {
 	return ok && hg.Hidden()
 }
 
-func isDescribableRouteGroup(g RouteGroup) bool {
-	if _, ok := g.(DescribableGroupIter); ok {
-		return true
-	}
-	if _, ok := g.(DescribableGroup); ok {
-		return true
-	}
-	return false
-}
-
 // routeDescriptions returns OpenAPI route descriptions for a group.
 // Iterator-backed implementations are preferred when available so builders
 // can avoid slice allocation.