keycloak-setup step hangs forever

[wirepatch]

Second step from README.md (apparently) hangs forever:

compose="docker compose -f build-contracts/docker-compose.yml"
$compose up --build -d keycloak openidc        # Executes well within ~3 seconds
$compose up --build keycloak-setup             # Hangs indefinitely causing 100% CPU load

Visiting a second terminal reveals:

ps aux
USER         PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
...
root       17819  0.0  0.0   4344  1280 ?        Ss   18:58   0:00 /bin/sh -c apt-get update   && apt-get install -y --no-install-recommends curl
root       17835  0.0  0.0  29104  4352 ?        S    18:58   0:00 apt-get update
root       17836 99.7  0.0  29100   792 ?        R    18:58   1:16 apt-get update
...

Manually aborted after ~500 seconds.