test(04-01): add failing tests for MarketplaceCard component

- 5 tests: name+description rendering, category badge, activate button,
  activated status badge, onToggle callback
- Tests fail as expected (RED phase) - component not yet implemented

apps/web/src/app/(portal)/marketplace/components/MarketplaceCard.test.tsx

@@ -0,0 +1,78 @@
+import { cleanup, render, screen } from '@testing-library/react';
+import userEvent from '@testing-library/user-event';
+import { afterEach, describe, expect, it, vi } from 'vitest';
+
+// Mock next-intl useTranslations
+vi.mock('next-intl', () => ({
+  useTranslations: () => (key: string) => {
+    const translations: Record<string, string> = {
+      activate: 'Modul aktivieren',
+      deactivate: 'Deaktivieren',
+      statusActive: 'Aktiviert',
+      statusAvailable: 'Verfuegbar',
+    };
+    return translations[key] ?? key;
+  },
+}));
+
+import { MarketplaceCard } from './MarketplaceCard';
+
+const baseProps = {
+  id: 'mod-1',
+  name: 'Domaincheck',
+  slug: 'domaincheck',
+  description: { de: 'Pruefe ob eine Domain verfuegbar ist', en: 'Check if a domain is available' },
+  icon: 'Globe',
+  category: 'Domain-Tools',
+  isActive: false,
+  isToggling: false,
+  onToggle: vi.fn(),
+};
+
+afterEach(() => {
+  cleanup();
+  vi.clearAllMocks();
+});
+
+describe('MarketplaceCard', () => {
+  it('renders the module name and the localized description (de locale)', () => {
+    render(<MarketplaceCard {...baseProps} />);
+
+    expect(screen.getByText('Domaincheck')).toBeInTheDocument();
+    expect(screen.getByText('Pruefe ob eine Domain verfuegbar ist')).toBeInTheDocument();
+  });
+
+  it('renders a category badge showing the module category', () => {
+    render(<MarketplaceCard {...baseProps} />);
+
+    expect(screen.getByText('Domain-Tools')).toBeInTheDocument();
+  });
+
+  it('shows the activate button and available status badge when isActive is false', () => {
+    render(<MarketplaceCard {...baseProps} isActive={false} />);
+
+    expect(screen.getByRole('button', { name: 'Modul aktivieren' })).toBeInTheDocument();
+    const statusBadge = screen.getByRole('status');
+    expect(statusBadge).toHaveTextContent('Verfuegbar');
+  });
+
+  it('shows a green Aktiviert status badge and the deactivate label when isActive is true', () => {
+    render(<MarketplaceCard {...baseProps} isActive={true} />);
+
+    const statusBadge = screen.getByRole('status');
+    expect(statusBadge).toHaveTextContent('Aktiviert');
+    expect(screen.getByRole('button', { name: 'Deaktivieren' })).toBeInTheDocument();
+  });
+
+  it('calls onToggle with the module id and the current active state when clicking the button', async () => {
+    const onToggle = vi.fn();
+    const user = userEvent.setup();
+
+    render(<MarketplaceCard {...baseProps} onToggle={onToggle} isActive={false} />);
+
+    await user.click(screen.getByRole('button', { name: 'Modul aktivieren' }));
+
+    expect(onToggle).toHaveBeenCalledOnce();
+    expect(onToggle).toHaveBeenCalledWith('mod-1', false);
+  });
+});