Add post-video redirect to YouTube URL from env config.

After the intro finishes, users are redirected to POST_VIDEO_REDIRECT_URL loaded via generated config.js for dev, Docker, and Dokploy deployments.

Co-authored-by: Cursor <cursoragent@cursor.com>

docker-compose.dev.yml

@@ -5,8 +5,13 @@ services:
   frontend:
     image: nginx:1.27-alpine
     build: !reset null
+    env_file:
+      - .env
+    environment:
+      POST_VIDEO_REDIRECT_URL: ${POST_VIDEO_REDIRECT_URL:-https://www.youtube.com/watch?v=kujXXtoHUbc}
     volumes:
       - ./index.html:/usr/share/nginx/html/index.html:ro
+      - ./config.js:/usr/share/nginx/html/config.js:ro
       - ./site.webmanifest:/usr/share/nginx/html/site.webmanifest:ro
       - ./assets:/usr/share/nginx/html/assets:ro
       - ./default.conf:/etc/nginx/conf.d/default.conf:ro