test(e2e): scope the AI-read card-marker assertion to desktop

The vault timeline is virtualized; on the narrow mobile viewport the seeded
Radiology-note card renders outside the initial virtual window (not in the
DOM), so the card-level attribute read waited out the full test timeout on a
non-existent node. The provenance contract is asserted on every project via
the detail status pill; the card marker (viewport-independent render logic,
also covered by the SSR card test) is asserted on desktop where the card is
reliably in view.

e2e/documents-ai.spec.ts

@@ -352,33 +352,36 @@ test.describe("document vault — AI assist + content search", () => {
 
   test("a vision-indexed document surfaces the AI-read provenance", async ({
     page,
-  }) => {
+  }, testInfo) => {
     // CONTENT_DOC_ID is seeded with source "vision" (an AI provider read it).
     // No mocks: the real list/detail GET threads the provenance through.
     await page.goto(`/documents?doc=${CONTENT_DOC_ID}`);
     const sheet = page.getByRole("dialog");
     await expect(sheet).toBeVisible();
 
-    // The detail status pill reflects the AI-read source.
+    // The detail status pill reflects the AI-read source — asserted on every
+    // project (this is the provenance contract; it holds on desktop + mobile).
     const status = sheet.locator('[data-slot="content-search-status"]');
     await expect(status).toHaveAttribute("data-state", "ai-read");
     await expect(status).toHaveText(/Read by AI/);
 
-    // The timeline card marks the same document with the AI-read Sparkles.
-    await page.keyboard.press("Escape");
-    const marker = page
-      .locator('[data-slot="document-card"]', { hasText: "Radiology note" })
-      .locator('[data-slot="document-searchable"]')
-      .first();
-    // The card marker appears after the list query invalidates and refetches
-    // the new provenance; on a loaded runner that round-trip can outlast the
-    // default 5s expect timeout, so wait explicitly for it to resolve. Scroll
-    // it into view first — the mobile timeline can render the card outside the
-    // viewport, where the attribute read intermittently misses it.
-    await marker.scrollIntoViewIfNeeded();
-    await expect(marker).toHaveAttribute("data-source", "ai-read", {
-      timeout: 20_000,
-    });
+    // The timeline card carries the same AI-read marker — desktop only. The
+    // vault timeline is virtualized; on the narrow mobile viewport the seeded
+    // card renders outside the initial virtual window (not in the DOM), so a
+    // card-level attribute read there tests the virtualizer, not the marker.
+    // The marker's render logic is viewport-independent and covered by the SSR
+    // card test + this desktop assertion; mobile provenance is already proven
+    // by the status pill above.
+    if (testInfo.project.name !== "chromium-mobile") {
+      await page.keyboard.press("Escape");
+      const marker = page
+        .locator('[data-slot="document-card"]', { hasText: "Radiology note" })
+        .locator('[data-slot="document-searchable"]')
+        .first();
+      await expect(marker).toHaveAttribute("data-source", "ai-read", {
+        timeout: 20_000,
+      });
+    }
   });
 
   // ── (f) Text-mode refuses a non-image before any OCR/upload ──────────────