Cache music as mp3 files on startup

Dockerfile

@@ -18,6 +18,7 @@ COPY package.json ./
 RUN bun install --production --ignore-scripts
 
 COPY --from=build /app/build ./build
+RUN mkdir -p /app/.cache/music && chown -R bun:bun /app/.cache
 
 ENV NODE_ENV=production
 ENV PORT=3000