perf(前端): 优化页面加载性能和用户体验

- 添加路由预加载功能，使用 requestIdleCallback 在浏览器空闲时预加载
- 配置 Vite manualChunks 分离 vendor 库（vue/ui/chart/i18n/misc）
- 新增 NavigationProgress 导航进度条组件，支持防闪烁和无障碍
- 集成 Vitest 测试框架，添加 40 个单元测试和集成测试
- 支持 prefers-reduced-motion 和暗色模式

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/src/components/common/__tests__/NavigationProgress.spec.ts

@@ -0,0 +1,83 @@
+/**
+ * NavigationProgress 组件单元测试
+ */
+import { describe, it, expect, vi, beforeEach } from 'vitest'
+import { mount } from '@vue/test-utils'
+import { ref } from 'vue'
+import NavigationProgress from '../../common/NavigationProgress.vue'
+
+// Mock useNavigationLoadingState
+const mockIsLoading = ref(false)
+
+vi.mock('@/composables/useNavigationLoading', () => ({
+  useNavigationLoadingState: () => ({
+    isLoading: mockIsLoading
+  })
+}))
+
+describe('NavigationProgress', () => {
+  beforeEach(() => {
+    mockIsLoading.value = false
+  })
+
+  it('isLoading=false 时进度条应该隐藏', () => {
+    mockIsLoading.value = false
+    const wrapper = mount(NavigationProgress)
+
+    const progressBar = wrapper.find('.navigation-progress')
+    // v-show 会设置 display: none
+    expect(progressBar.isVisible()).toBe(false)
+  })
+
+  it('isLoading=true 时进度条应该可见', async () => {
+    mockIsLoading.value = true
+    const wrapper = mount(NavigationProgress)
+
+    await wrapper.vm.$nextTick()
+
+    const progressBar = wrapper.find('.navigation-progress')
+    expect(progressBar.exists()).toBe(true)
+    expect(progressBar.isVisible()).toBe(true)
+  })
+
+  it('应该有正确的 ARIA 属性', () => {
+    mockIsLoading.value = true
+    const wrapper = mount(NavigationProgress)
+
+    const progressBar = wrapper.find('.navigation-progress')
+    expect(progressBar.attributes('role')).toBe('progressbar')
+    expect(progressBar.attributes('aria-label')).toBe('Loading')
+    expect(progressBar.attributes('aria-valuemin')).toBe('0')
+    expect(progressBar.attributes('aria-valuemax')).toBe('100')
+  })
+
+  it('进度条应该有动画 class', () => {
+    mockIsLoading.value = true
+    const wrapper = mount(NavigationProgress)
+
+    const bar = wrapper.find('.navigation-progress-bar')
+    expect(bar.exists()).toBe(true)
+  })
+
+  it('应该正确响应 isLoading 状态变化', async () => {
+    // 测试初始状态为 false
+    mockIsLoading.value = false
+    const wrapper = mount(NavigationProgress)
+    await wrapper.vm.$nextTick()
+
+    // 初始状态隐藏
+    expect(wrapper.find('.navigation-progress').isVisible()).toBe(false)
+
+    // 卸载后重新挂载以测试 true 状态
+    wrapper.unmount()
+
+    // 改变为 true 后重新挂载
+    mockIsLoading.value = true
+    const wrapper2 = mount(NavigationProgress)
+    await wrapper2.vm.$nextTick()
+    expect(wrapper2.find('.navigation-progress').isVisible()).toBe(true)
+
+    // 清理
+    wrapper2.unmount()
+  })
+})