Root cause: ubuntu:24.04 has no CA certificates, rustls-native-certs fails TLS handshake. Fix: apt-get install ca-certificates before running download binary. Also add port 80 to network policy for apt. Downloads OHLCV-1m, Trades, OHLCV-1s, MBP-10 via streaming API (get_range) — parallel quarterly downloads, individual .dbn.zst files. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>