feat(billing): guide parents to recharge the child account

tests/unit/sidebar-token-points.test.tsx

@@ -91,6 +91,7 @@ describe('Sidebar permanent point wallet', () => {
     expect(screen.queryByText(/重置卡|升级订阅|会员等级|本周剩余/)).not.toBeInTheDocument();
     fireEvent.click(screen.getByTestId('sidebar-point-wallet-open'));
     expect(screen.getByTestId('point-wallet-dialog')).toHaveTextContent('1 元充值 50 点');
+    expect(screen.getByTestId('point-recharge-recipient')).toHaveTextContent('测试用户（member@example.com）');
   });
   it('shows a retryable failure without inventing a zero balance', async () => {
     fetchBillingSummaryMock.mockRejectedValue(new Error('offline'));