Caddy was decompressing nginx's gzip responses and sending them
uncompressed to the browser, causing core-common.js (5.7MB) to
take 25s to download. Adding encode zstd gzip compresses it to
1.3MB at the edge.
Replace the all-in-one Apache image with nextcloud:33-fpm and an Nginx
sidecar that serves static assets directly with gzip compression and
cache headers, avoiding the prefork concurrency bottleneck.
