Add YouTube playback and queue flow

docker-compose-example.yml

@@ -9,6 +9,7 @@ services:
     environment:
       PORT: "3000"
       NODE_ENV: production
+      YT_DLP_TIMEOUT_MS: "45000"
       # split: smoothest, two upstream connections.
       # relay: one upstream connection, separate audio/frame ffmpeg workers.
       # single: one upstream connection and one ffmpeg worker; fallback only.