feat: expose possible values

include/ApiServer.h

@@ -28,6 +28,7 @@ public:
         bool required;
         String location; // "query" | "body" | "path" | "header"
         String type;     // e.g. "string", "number", "boolean"
+        std::vector<String> values; // optional allowed values
     };
     struct EndpointCapability {
         String uri;