test(api): 处理器测试的每次请求在包结束后对照 openapi 校验状态码、响应与 2xx 请求体，SetupAllowed 纳入一致性比对，补齐漏记的状态码并修正空列表回 null

internal/api/handlers_internal.go

@@ -43,6 +43,9 @@ func (a *API) handleListServers(w http.ResponseWriter, r *http.Request) {
 		writeError(w, r, err)
 		return
 	}
+	if servers == nil {
+		servers = []ServerInfo{} // an empty fleet is [], never null
+	}
 	writeJSON(w, http.StatusOK, map[string]any{"servers": servers})
 }