fix: install Node.js and use web client for YouTube n-challenge solving

- ios player client doesn't support cookies, switch to web
- Node.js is required for yt-dlp to solve YouTube's n-challenge;
  without it only image formats are served

Dockerfile

@@ -3,6 +3,7 @@ FROM python:3.11-slim
 RUN apt-get update && apt-get install -y --no-install-recommends \
     ffmpeg \
     curl \
+    nodejs \
     && rm -rf /var/lib/apt/lists/*
 
 WORKDIR /app