test(webui): find the composer's file inputs by the class they carry now

The shared presentation layer replaced the composer's own hidden file inputs
with the shared `WebuiFileInput`, and the shared component gives every file
input the class `webui-file-input`. The composer's `webui-composer-hidden-file-input`
class went with the old markup.

Two test files still looked for the removed class, so the locator matched
nothing and the cases that attached a file timed out waiting for an element
that was never there.

Author: stevenjj33

packages/webui/test/browser/composer.spec.mjs

@@ -265,7 +265,7 @@ test("history is per session — B's submissions do not leak into A", async ({ p
 test("attaching a file and an image renders chips that can be removed", async ({ page }) => {
   await openApp(page, "#session=A");
 
-  const fileInput = page.locator('input.webui-composer-hidden-file-input[aria-label="添加文件或图片"]');
+  const fileInput = page.locator('input.webui-file-input[aria-label="添加文件或图片"]');
   await fileInput.setInputFiles([
     { name: "notes.txt", mimeType: "text/plain", buffer: Buffer.from("hello attachment") },
     { name: "pixel.png", mimeType: "image/png", buffer: TINY_PNG },
@@ -295,7 +295,7 @@ test("the directory input accepts a folder selection and renders its chips", asy
     mkdirSync(path.join(folder, "src"));
     writeFileSync(path.join(folder, "root.txt"), "root");
     writeFileSync(path.join(folder, "src", "main.ts"), "export {};\n");
-    const folderInput = page.locator('input.webui-composer-hidden-file-input[aria-label="添加本地文件夹"]');
+    const folderInput = page.locator('input.webui-file-input[aria-label="添加本地文件夹"]');
     await folderInput.setInputFiles(folder);
     const chips = page.locator('[data-webui-composer-attachments="true"]');
     await expect(chips).toBeVisible();

packages/webui/test/integration/agent-transcript.test.ts

@@ -1041,7 +1041,7 @@ it("a real agent turn resumes after refresh and drains a queued message in order
     expect(modelRequests.some((request) => request.body.includes("Create a task checklist.") &&
       request.body.includes("todowrite"))).toBe(true);
 
-    const attachmentInput = page.locator('input.webui-composer-hidden-file-input[aria-label="添加文件或图片"]');
+    const attachmentInput = page.locator('input.webui-file-input[aria-label="添加文件或图片"]');
     await attachmentInput.setInputFiles({
       name: "runtime-note.txt",
       mimeType: "text/plain",