Replace startup mocks with loading skeletons

src/App.test.tsx

@@ -9,6 +9,12 @@ async function loginIntoPanel(user: ReturnType<typeof userEvent.setup>) {
   await user.type(screen.getByLabelText(/login/i), 'admin');
   await user.type(screen.getByLabelText(/password/i), 'proxy-ui-demo');
   await user.click(screen.getByRole('button', { name: /open panel/i }));
+  await waitFor(() => expect(MockWebSocket.instances.length).toBeGreaterThan(0));
+  MockWebSocket.instances.at(-1)?.emitMessage({
+    type: 'snapshot.init',
+    snapshot: fallbackDashboardSnapshot,
+  });
+  await waitFor(() => expect(screen.getByRole('button', { name: /settings/i })).not.toBeDisabled());
 }
 
 function mockClipboardWriteText(writeText: ReturnType<typeof vi.fn>) {
@@ -64,6 +70,19 @@ describe('App login gate', () => {
     expect(screen.queryByRole('button', { name: /open panel/i })).not.toBeInTheDocument();
   });
 
+  it('shows loading skeletons instead of stale mock values before the first snapshot arrives', async () => {
+    const user = userEvent.setup();
+    render(<App />);
+
+    await user.type(screen.getByLabelText(/login/i), 'admin');
+    await user.type(screen.getByLabelText(/password/i), 'proxy-ui-demo');
+    await user.click(screen.getByRole('button', { name: /open panel/i }));
+
+    expect(screen.getByRole('navigation', { name: /primary/i })).toBeInTheDocument();
+    expect(screen.queryByText(/edge\.example\.net/i)).not.toBeInTheDocument();
+    expect(document.querySelectorAll('.skeleton-line').length).toBeGreaterThan(0);
+  });
+
   it('stores panel language in localStorage and restores it after a remount', async () => {
     const user = userEvent.setup();
     const firstRender = render(<App />);