feat: add video thumbnail support for cover images

- Add YouTube thumbnail extraction using existing getYouTubeThumbnail utility
- Add Vimeo thumbnail support using vumbnail.com service
- Update VideoView to use video thumbnails as cover images in ReaderHeader
- Update Vimeo API to include thumbnail_url in response
- Fallback to original image prop if no video thumbnail available
- Supports both YouTube and Vimeo video thumbnails

api/video-meta.ts

@@ -94,7 +94,7 @@ async function pickCaptions(videoID: string, preferredLangs: string[], manualFir
   return null
 }
 
-async function getVimeoMetadata(videoId: string): Promise<{ title: string; description: string }> {
+async function getVimeoMetadata(videoId: string): Promise<{ title: string; description: string; thumbnail_url?: string }> {
   const vimeoUrl = `https://vimeo.com/${videoId}`
   const oembedUrl = `https://vimeo.com/api/oembed.json?url=${encodeURIComponent(vimeoUrl)}`
   
@@ -107,7 +107,8 @@ async function getVimeoMetadata(videoId: string): Promise<{ title: string; descr
   
   return {
     title: data.title || '',
-    description: data.description || ''
+    description: data.description || '',
+    thumbnail_url: data.thumbnail_url || ''
   }
 }
 
@@ -197,11 +198,12 @@ export default async function handler(req: VercelRequest, res: VercelResponse) {
       return ok(res, response)
     } else if (videoInfo.source === 'vimeo') {
       // Vimeo handling
-      const { title, description } = await getVimeoMetadata(videoInfo.id)
+      const { title, description, thumbnail_url } = await getVimeoMetadata(videoInfo.id)
       
       const response = {
         title,
         description,
+        thumbnail_url,
         captions: [], // Vimeo doesn't provide captions through oEmbed API
         transcript: '', // No transcript available
         lang: 'en', // Default language

src/components/VideoView.tsx

@@ -7,6 +7,16 @@ import { IAccount } from 'applesauce-accounts'
 import { UserSettings } from '../services/settingsService'
 import { extractYouTubeId, getYouTubeMeta } from '../services/youtubeMetaService'
 import { buildNativeVideoUrl } from '../utils/videoHelpers'
+import { getYouTubeThumbnail } from '../utils/imagePreview'
+
+// Helper function to get Vimeo thumbnail
+const getVimeoThumbnail = (url: string): string | null => {
+  const vimeoMatch = url.match(/vimeo\.com\/(\d+)/)
+  if (!vimeoMatch) return null
+  
+  const videoId = vimeoMatch[1]
+  return `https://vumbnail.com/${videoId}.jpg`
+}
 import { 
   createWebsiteReaction,
   hasMarkedWebsiteAsRead
@@ -201,12 +211,18 @@ const VideoView: React.FC<VideoViewProps> = ({
   const displayTitle = ytMeta?.title || title
   const displaySummary = ytMeta?.description || summary
   const durationText = videoDurationSec !== null ? formatDuration(videoDurationSec) : null
+  
+  // Get video thumbnail for cover image
+  const youtubeThumbnail = getYouTubeThumbnail(videoUrl)
+  const vimeoThumbnail = getVimeoThumbnail(videoUrl)
+  const videoThumbnail = youtubeThumbnail || vimeoThumbnail
+  const displayImage = videoThumbnail || image
 
   return (
     <>
       <ReaderHeader 
         title={displayTitle}
-        image={image}
+        image={displayImage}
         summary={displaySummary}
         published={published}
         readingTimeText={durationText}