修正讲解音频时长显示

- 未加载媒体元数据时默认显示零时长
- 使用音频文件真实媒体时长更新播放器
- 避免使用不准确的接口时长覆盖播放器显示
- 补充音频时长回归测试

Made-with: Proma

tests/unit/ExhibitDetailAudioFirst.spec.ts

@@ -172,7 +172,7 @@ describe('讲解详情音频优先布局', () => {
     expect(wrapper.get('.content-section').classes()).toContain('is-english')
     expect(wrapper.find('.section-title').exists()).toBe(false)
     expect(wrapper.get('.section-text').text()).toContain('detailed English narration')
-    expect(wrapper.get('.detail-audio-time').text()).toBe('0:00 / 1:21')
+    expect(wrapper.get('.detail-audio-time').text()).toBe('0:00 / 0:00')
     expect(wrapper.get('.detail-audio-speed').attributes('aria-label')).toBe('播放速度 1.0倍')
   })
 

tests/unit/GlobalAudioPlayerLanguage.spec.ts

@@ -20,6 +20,26 @@ describe('全局讲解播放器语言切换', () => {
     vi.unstubAllGlobals()
   })
 
+  it('媒体元数据加载前忽略接口时长，加载后使用音频真实时长', () => {
+    const audio = document.createElement('audio')
+    vi.spyOn(window, 'Audio').mockImplementation(() => audio)
+
+    player.prepare({
+      id: 'duration-audio',
+      name: '时长测试',
+      audioUrl: '/museum-assets/audio/duration.mp3',
+      duration: 28,
+      language: 'zh-CN'
+    })
+
+    expect(player.duration.value).toBe(0)
+
+    Object.defineProperty(audio, 'duration', { configurable: true, value: 54.974938 })
+    audio.dispatchEvent(new Event('loadedmetadata'))
+
+    expect(player.duration.value).toBeCloseTo(54.974938)
+  })
+
   it('切换到粤语时只从当前统一详情的音轨数组选择，不产生额外 HTTP 请求', async () => {
     const request = vi.fn()
     vi.stubGlobal('uni', { request, showToast: vi.fn() })