feat: update ApkList to use tabbed view

Replaced card-based layout with tabbed interface for APK environments.
Now displays APKs grouped by dev/product/sandbox/other tabs with counts.

- Replaced ApkCard with ApkTable component
- Added tab navigation with active state styling
- Group APKs by environment using reduce
- Show count badges for each environment tab

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/download/__tests__/ApkList.test.tsx

@@ -0,0 +1,85 @@
+import React from 'react';
+import { render, screen, fireEvent } from '@testing-library/react';
+import ApkList from '../ApkList';
+import useSWR from 'swr';
+
+jest.mock('swr');
+
+describe('ApkList', () => {
+  const mockApks = [
+    {
+      name: 'ft_timeshift_0_42_57ef3a60d.apk',
+      environment: 'dev',
+      commit: '57ef3a60d',
+      size: 15728640,
+      modifiedAt: '2026-03-04T14:30:00.000Z',
+      downloadUrl: '/api/download?project=FT&version=0_42&filename=ft_timeshift_0_42_57ef3a60d.apk',
+    },
+    {
+      name: 'ft_0_42_ff9ff3441.apk',
+      environment: 'product',
+      commit: 'ff9ff3441',
+      size: 15728640,
+      modifiedAt: '2026-03-04T14:30:00.000Z',
+      downloadUrl: '/api/download?project=FT&version=0_42&filename=ft_0_42_ff9ff3441.apk',
+    },
+    {
+      name: 'ft_sandbox_0_42_57ef3a60d.apk',
+      environment: 'sandbox',
+      commit: '57ef3a60d',
+      size: 15728640,
+      modifiedAt: '2026-03-04T14:30:00.000Z',
+      downloadUrl: '/api/download?project=FT&version=0_42&filename=ft_sandbox_0_42_57ef3a60d.apk',
+    },
+  ];
+
+  beforeEach(() => {
+    (useSWR as jest.Mock).mockReturnValue({
+      data: mockApks,
+      isLoading: false,
+      error: null,
+    });
+  });
+
+  it('should render all 4 tabs', () => {
+    render(<ApkList project="FT" version="0_42" commitId="" />);
+
+    expect(screen.getByText(/dev/)).toBeInTheDocument();
+    expect(screen.getByText(/product/)).toBeInTheDocument();
+    expect(screen.getByText(/sandbox/)).toBeInTheDocument();
+    expect(screen.getByText(/other/)).toBeInTheDocument();
+  });
+
+  it('should switch tabs correctly', () => {
+    render(<ApkList project="FT" version="0_42" commitId="" />);
+
+    const devTab = screen.getByText(/dev/);
+    fireEvent.click(devTab);
+
+    expect(screen.getByText('57ef3a60d')).toBeInTheDocument();
+  });
+
+  it('should show loading state', () => {
+    (useSWR as jest.Mock).mockReturnValue({
+      data: null,
+      isLoading: true,
+      error: null,
+    });
+
+    render(<ApkList project="FT" version="0_42" commitId="" />);
+
+    expect(screen.getByText('加载中...')).toBeInTheDocument();
+  });
+
+  it('should show error state', () => {
+    (useSWR as jest.Mock).mockReturnValue({
+      data: null,
+      isLoading: false,
+      error: new Error('API error'),
+    });
+
+    render(<ApkList project="FT" version="0_42" commitId="" />);
+
+    expect(screen.getByText('加载失败，请重试')).toBeInTheDocument();
+  });
+});