add script to download missing YT thumbnails

.github/workflows/build.yml

@@ -16,6 +16,14 @@ jobs:
           node-version: 20
           cache: "npm"
 
+      - name: Download YT Thumbnails
+        run: |
+          for file in $(grep -roP 'youtube-nocookie.com/embed/.{11}' docs | rev | cut -d / -f 1 | rev); do
+            if [ ! -f "static/img/yt_thumbnails/$file.jpg" ]; then
+              wget -O "static/img/yt_thumbnails/$file-hq.jpg" "https://img.youtube.com/vi/$file/hqdefault.jpg" || wget -O "static/img/yt_thumbnails/$file.jpg" "https://img.youtube.com/vi/$file/0.jpg"
+            fi
+          done
+
       - name: Build
         id: build
         run: |