Add infra/flowable/docker-compose.yml (flowable-rest on Postgres, host :8090)
and workflows/registratie.bpmn — a minimal "Registratie ontvangen" process:
start -> external-worker task OpenZaakAanmaken -> end. A flowable-init
container deploys the model via the REST API on boot (idempotent: skips if
already deployed).
Add `make flowable-up/flowable-smoke/flowable-down`; flowable-smoke runs
infra/flowable/verify.py, which starts an instance and asserts it parks on
the OpenZaakAanmaken external task, then cleans up. Runbook included.
Verified clean-slate: down --volumes -> `make flowable-smoke` deploys on
boot, starts an instance, and confirms it waits at OpenZaakAanmaken.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
