refactor: unify data preparations and research input snapshots

frontend/tests/research-flows.spec.ts

@@ -1,3 +1,4 @@
+import { choosePreparation } from "./preparation-helpers";
 import { expect, test } from "@playwright/test";
 const headers = { "X-WQ-Request": "1" };
 const scope = {
@@ -71,13 +72,12 @@ test("finite pipeline confirms scope and budget, executes native steps and resto
     await page.request.get(`/api/v1/catalog/datasets/TEST_FIN/fields?${params}`)
   ).json();
   const fixed = await (
-    await page.request.post("/api/v1/catalog/inputs", {
+    await page.request.post("/api/v1/data-preparations/from-dataset", {
       headers,
       data: {
         scope,
         dataset_id: "TEST_FIN",
         collection_version: fields.collection_version,
-        selection: "all",
       },
     })
   ).json();
@@ -97,11 +97,7 @@ test("finite pipeline confirms scope and budget, executes native steps and resto
   await page.getByRole("button", { name: "新建自动研究", exact: true }).click();
   await page.getByLabel("自动研究名称").fill("浏览器有限研究");
   await page.getByLabel("自动研究假设").fill("研究排名稳定性");
-  await page.getByRole("combobox", { name: "自动研究固定输入" }).click();
-  await page
-    .getByRole("option")
-    .filter({ hasText: fixed.id.slice(0, 8) })
-    .click();
+  await choosePreparation(page, fixed.name, "选择研究数据准备");
   await page.getByLabel("自动研究名称").click();
   for (const [label, value] of [
     ["最大轮数", "1"],