fix(files): a row's picture fits its box on iPad

In a table cell WebKit resolved the picture's h-full against the aspect-video box as the poster's own height, so the box showed a native-size sliver of it. The box now has a fixed 16:9 height, as the other pictures in tables do; an e2e check runs in the WebKit and iPad projects.

frontend/e2e/files.spec.ts

@@ -24,6 +24,52 @@ test.describe("Files", () => {
     await expect(dialog(page)).toBeHidden();
   });
 
+  // WebKit (every iPad browser) cannot resolve a percentage height against a box whose height comes
+  // from aspect-ratio inside a table cell: the picture took its own full height and the 16:9 box
+  // showed a native-size sliver of it, a blur of colour. The library is stubbed with one file whose
+  // poster is a tall picture, the case that shows it most.
+  test("a row's picture fits its box", async ({ page }) => {
+    const file = {
+      id: 990001,
+      status: "done",
+      progress: 100,
+      created_at: "2026-11-14T10:00:00+00:00",
+      source_kind: "youtube",
+      source_ref: "e2e-thumb",
+      source_url: null,
+      poster_url: "/api/downloads/990001/poster.jpg",
+      display_name: "A tall poster",
+      display_uploader: null,
+      extra_links: [],
+      can_download: true,
+      job_kind: "download",
+      folder_id: null,
+      kept: false,
+      expires_at: null,
+      shared: false,
+      source_key: "youtube",
+      asset: { media_kind: "video", duration_s: 60, size_bytes: 2048 },
+    };
+    await page.route(/\/api\/files(\?|$)/, (route) => route.fulfill({ json: [file] }));
+    await page.route(/\/api\/downloads\/990001\/poster\.jpg/, (route) =>
+      route.fulfill({
+        contentType: "image/svg+xml",
+        body: '<svg xmlns="http://www.w3.org/2000/svg" width="1080" height="1920"><rect width="1080" height="1920" fill="#3a6"/></svg>',
+      }),
+    );
+    // Wide enough that the picture column shows beside a pinned rail (an iPad Pro in landscape).
+    await page.setViewportSize({ width: 1366, height: 1024 });
+    await openApp(page);
+    await gotoPage(page, "files");
+    const picture = page.getByRole("row", { name: /A tall poster/ }).locator("img");
+    await expect(picture).toBeVisible();
+    const fit = await picture.evaluate((img) => {
+      const box = img.parentElement!.getBoundingClientRect();
+      return { img: img.getBoundingClientRect().height, box: box.height };
+    });
+    expect(fit.img).toBeLessThanOrEqual(fit.box);
+  });
+
   test("a link pasted onto a page (not into a field) opens the download dialog", async ({
     page,
   }) => {