Closes#510.
`docker compose up -d --wait` exits 1 even when every service is
healthy because the one-shot `create-buckets` exits 0 and --wait
expects "running". The whole stack came up fine on staging, but the
workflow gate failed before the smoke step could run.
Two changes:
1. create-buckets: `restart: "no"` declares one-shot intent.
2. backend.depends_on: add `create-buckets: service_completed_successfully`.
With both, compose v2.20+ understands create-buckets is a one-shot
that must complete successfully, and --wait treats exited(0) as the
target state. Backend startup now also correctly gates on bucket
bootstrap (closes a latent race where backend could start before
the archiv-app policy was bound).
Verified `docker compose config --quiet` parses and the resolved
config shows the right dependency graph.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
