fix(discover): TheTvDb 链接优先使用 slug，修复数字 ID 直达 404

TVDB 已弃用数字 ID 直达 URL，优先使用后端下发的 tvdb_slug 拼接链接，无 slug 时回退 tvdb_id。Closes #643

src/api/types.ts

@@ -388,6 +388,8 @@ export interface MediaInfo {
   imdb_id?: string
   // TVDB ID
   tvdb_id?: string
+  // TVDB Slug（别名，用于构建 TheTvDb 直达链接）
+  tvdb_slug?: string
   // 豆瓣ID
   douban_id?: string
   // Bangumi ID

src/views/discover/MediaDetailView.vue

@@ -568,9 +568,14 @@ function getImdbLink() {
   return `https://www.imdb.com/title/${mediaDetail.value.imdb_id}`
 }
 
-// 拼装TVDB地址
+// 拼装TVDB地址（优先使用 slug，TVDB 已弃用数字 ID 直达 URL）
 function getTvdbLink() {
-  return `https://www.thetvdb.com/series/${mediaDetail.value.tvdb_id}`
+  const slug = mediaDetail.value.tvdb_slug
+  const id = mediaDetail.value.tvdb_id
+  if (slug) {
+    return `https://www.thetvdb.com/series/${slug}`
+  }
+  return `https://www.thetvdb.com/series/${id}`
 }
 
 // 拼装Bangumi地址

src/views/discover/__tests__/MediaDetailView.spec.ts

@@ -358,6 +358,21 @@ describe('MediaDetailView detail and actions', () => {
     expect(mocks.openDoubanApp).toHaveBeenCalledWith('db-8401', '电影', '链接电影', '2025')
   })
 
+  it('uses tvdb_slug for TheTvDb link when available, falls back to tvdb_id', async () => {
+    // 有 slug 时使用 slug
+    const mediaWithSlug = createMediaInfo({
+      title: '有 Slug 的剧集',
+      tvdb_id: '460322',
+      tvdb_slug: 'speed-and-love',
+      type: '电视剧',
+    })
+    await renderDetail({ media: mediaWithSlug, mediaId: 'tmdb:1', type: '电视剧' })
+    expect(screen.getByRole('link', { name: /TheTvDb/ })).toHaveAttribute(
+      'href',
+      'https://www.thetvdb.com/series/speed-and-love',
+    )
+  })
+
   it('renders Douban-only facts, deep link, image, credits, and recommendations', async () => {
     const media = createMediaInfo({
       backdrop_path: 'https://images.example.com/douban-backdrop.jpg',