ci: install Playwright chromium for the storybook vitest project; deterministic in-flight test

- CI runs the @vitest/browser-playwright (storybook) project, which needs the
  chromium browser downloaded — add 'playwright install --with-deps chromium'.
- object-new-page in-flight test held the create mutation open with a 50ms
  delay and raced the pending-state assertion (failed under CI timing); gate it
  on a promise released only after asserting 'saving…', so it's deterministic.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.gitea/workflows/ci.yaml

@@ -26,6 +26,7 @@ jobs:
       - run: pnpm install --frozen-lockfile
       - run: pnpm typecheck
       - run: pnpm lint
+      - run: pnpm exec playwright install --with-deps chromium
       - run: pnpm test
       - run: pnpm build
       - run: pnpm check:size

web/src/objects/object-new-page.test.tsx

@@ -1,7 +1,7 @@
 import { expect, test } from "vitest";
 import { screen, waitFor } from "@testing-library/react";
 import userEvent from "@testing-library/user-event";
-import { delay, http, HttpResponse } from "msw";
+import { http, HttpResponse } from "msw";
 import { Routes, Route } from "react-router-dom";
 import { server } from "../test/server";
 import { renderApp } from "../test/render";
@@ -72,11 +72,15 @@ test("partial create: fields PUT fails -> edit page shows the 'created' banner a
 
 test("in-flight submit: button disabled + shows Saving…, create fires exactly once on double-click", async () => {
   let postCount = 0;
+  let release!: () => void;
+  const gate = new Promise<void>((resolve) => {
+    release = resolve;
+  });
 
   server.use(
     http.post("/api/admin/objects", async () => {
       postCount += 1;
-      await delay(50);
+      await gate;
       return HttpResponse.json({ id: "new-id-3" }, { status: 201 });
     }),
   );
@@ -91,9 +95,13 @@ test("in-flight submit: button disabled + shows Saving…, create fires exactly
   await userEvent.click(button);
   await userEvent.click(button);
 
-  await waitFor(() => expect(screen.getByText(/saving…/i)).toBeInTheDocument());
+  // The mutation is held open by `gate`, so the pending state is observed
+  // deterministically (no reliance on a timing window).
+  expect(await screen.findByText(/saving…/i)).toBeInTheDocument();
   expect(screen.getByRole("button", { name: /saving…/i })).toBeDisabled();
 
+  release();
+
   await waitFor(() => expect(screen.getByText("detail view")).toBeInTheDocument());
   expect(postCount).toBe(1);
 });