feat(worker): add logout + replace admin-only settings with Account screen

The Instellingen tab was activity management, which Phase 2 made admin-only —
workers saw add/edit/delete controls that all 403. Replace it with an Account
tab showing the signed-in name/email (via /api/me) and an Uitloggen button
(wires the existing AuthContext signOut). Activity management belongs to the
Phase 3 admin app, so the worker client drops the Settings screen and its
now-unused activity-mutation hooks (useActivities read stays).

Products affected: SoleLog worker client (apps/worker).

apps/worker/src/screens/Account.test.tsx

@@ -0,0 +1,54 @@
+import { render, screen } from '@testing-library/react';
+import userEvent from '@testing-library/user-event';
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
+import Account from './Account';
+import { AuthProvider } from '../auth/AuthContext';
+import { apiFetch } from '../lib/api';
+import { clearToken, getToken, setToken } from '../lib/auth-storage';
+
+// Mock the network layer so no real requests are made.
+vi.mock('../lib/api', () => ({
+  apiFetch: vi.fn(),
+}));
+
+const mockedApiFetch = vi.mocked(apiFetch);
+
+function renderAccount() {
+  const queryClient = new QueryClient({ defaultOptions: { queries: { retry: false } } });
+  return render(
+    <QueryClientProvider client={queryClient}>
+      <AuthProvider>
+        <Account />
+      </AuthProvider>
+    </QueryClientProvider>
+  );
+}
+
+describe('Account', () => {
+  beforeEach(() => {
+    mockedApiFetch.mockReset();
+    mockedApiFetch.mockResolvedValue({
+      user: { id: 'u1', email: 'worker@solelog.local', name: 'Test Werker' },
+    });
+  });
+
+  afterEach(() => {
+    clearToken();
+    vi.clearAllMocks();
+  });
+
+  it('shows the signed-in user name and email', async () => {
+    renderAccount();
+    expect(await screen.findByText('Test Werker')).toBeInTheDocument();
+    expect(screen.getByText('worker@solelog.local')).toBeInTheDocument();
+  });
+
+  it('logs out: clicking Uitloggen clears the token', async () => {
+    setToken('tok');
+    const user = userEvent.setup();
+    renderAccount();
+    await user.click(screen.getByRole('button', { name: 'Uitloggen' }));
+    expect(getToken()).toBeNull();
+  });
+});