test(app): cover sidebar empty-state actions staying inside the card

Renders the empty state in a real browser at the default sidebar width and
checks both actions' bounds against the card, for Russian (fails without the
wrap) and English.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packages/app/src/components/sidebar/empty-states.browser.test.tsx

@@ -0,0 +1,61 @@
+import React, { act } from "react";
+import { createRoot, type Root } from "react-dom/client";
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+import { i18n as testI18n } from "@/i18n/i18next";
+import { DEFAULT_SIDEBAR_WIDTH } from "@/stores/panel-store";
+import { SidebarProjectEmptyState } from "./empty-states";
+
+// App sources compile against the classic JSX runtime, which expects React on the global.
+beforeEach(() => vi.stubGlobal("React", React));
+
+interface Mounted {
+  root: Root;
+  container: HTMLDivElement;
+}
+
+const mounted: Mounted[] = [];
+
+afterEach(async () => {
+  for (const entry of mounted.splice(0)) {
+    act(() => entry.root.unmount());
+    entry.container.remove();
+  }
+  await testI18n.changeLanguage("en");
+});
+
+async function mountEmptyState(language: string, width: number): Promise<HTMLElement> {
+  await testI18n.changeLanguage(language);
+
+  const container = document.createElement("div");
+  container.style.width = `${width}px`;
+  document.body.appendChild(container);
+  const root = createRoot(container);
+  act(() => root.render(<SidebarProjectEmptyState />));
+  mounted.push({ root, container });
+
+  const card = container.querySelector('[data-testid="sidebar-project-empty-state"]');
+  if (!(card instanceof HTMLElement)) {
+    throw new Error("SidebarProjectEmptyState did not render its card");
+  }
+  return card;
+}
+
+// Translations of "Add project" and "Import session" can be wider than the default sidebar, so the
+// action row has to wrap instead of pushing the second button past the card's border.
+describe("SidebarProjectEmptyState", () => {
+  it.each([
+    ["ru", DEFAULT_SIDEBAR_WIDTH],
+    ["en", DEFAULT_SIDEBAR_WIDTH],
+  ])("keeps every action inside the card (%s, %ipx sidebar)", async (language, width) => {
+    const card = await mountEmptyState(language, width);
+    const cardRect = card.getBoundingClientRect();
+    const buttons = Array.from(card.querySelectorAll<HTMLElement>('[role="button"]'));
+
+    expect(buttons).toHaveLength(2);
+    for (const button of buttons) {
+      const rect = button.getBoundingClientRect();
+      expect(rect.left).toBeGreaterThanOrEqual(cardRect.left);
+      expect(rect.right).toBeLessThanOrEqual(cardRect.right);
+    }
+  });
+});