Three named targets (app, horizon, scheduler) sharing a runtime-base
with PHP 8.3-FPM, opcache, redis, and pinned php-fpm pool config.
Composer + Node build stages are separate so vendor/ and public/build/
are baked into the runtime image.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
