## What & why
S-09b (#75, split from #10) — the **approval flow** that completes the walking skeleton. A behandelaar can now approve a submitted registration; the entry flips from `INGEDIEND` to `INGESCHREVEN` in the public register. Flow: `POST /registrations/{id}/approve` (domain) → ACL sets the zaak eindstatus (ZGW `/statussen`) → OpenZaak → NRC → event-subscriber → projection → openbaar.
## Changes (bottom-up, each red→green TDD)
- **Domain** — `RegistrationStatus.Ingeschreven` + `Registration.Approve()` (guards: opened zaak, only from INGEDIEND); `ApproveRegistration` use case (idempotent) + temp `POST /registrations/{id}/approve` endpoint; `IAclClient.ApproveZaakAsync`.
- **ACL** — resolves the zaaktype's **eindstatus** from the catalogus (`isEindstatus` / highest volgnummer) and POSTs a ZGW status; exposed as `POST /statussen`. Unit + real-OpenZaak integration test.
- **Event-subscriber** — binds NRC `hoofdObject`, projects a `status`/`create` as `INGESCHREVEN` keyed on the zaak (updates the existing row), **without reading OpenZaak** (§8.1). Retains the ZGW `resource` in the log (new column + EF migration) so a rebuild reproduces the status.
- **e2e** — extended: submit → public INGEDIEND → approve → public INGESCHREVEN.
- **Docs** — ADR-0011 (the two non-obvious decisions + the walking-skeleton assumption) + demo note.
## Key decisions (see ADR-0011)
- **ACL discovers the eindstatus** (chosen over injecting a statustype URL): no new config/seed plumbing, domain stays ZGW-ignorant.
- **Any post-creation status-set ⇒ INGESCHREVEN**: in the walking skeleton the only status ever set after creation is the approval, and the subscriber may not read ZGW — documented to tighten when more transitions arrive (S-12+).
## Verification
- All .NET unit suites green locally (domain 47, acl 11, event-subscriber 14, bff 16, acceptance 7); Release build + `dotnet format` clean.
- No new compose config (the eindstatus-discovery approach avoided it).
- The real-OpenZaak integration test (ACL status-set) and the full submit→approve→visible e2e run in CI `verify-stack` (live NRC→projection + selectielijst egress, not reproducible locally).
closes#75
Reviewed-on: #77
Record the workspace/tooling decisions (pnpm, Nx scoped to apps/+libs/, Vitest,
no @nx/docker, no Nx Cloud, Gitea-only) and a demo note for running the placeholder
app. NL DS deferred to S-08c.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
ADR-0008 records the read-projection design: one rebuildable store shared by the Event
Subscriber (writer) and projection-api (reader) as one CQRS bounded context (reconciled
with §8.5), idempotency + rebuild from the notification log (no OpenZaak access, §8.1),
the deferred bsn/naam, and the new EF Core + Npgsql dependency. Add a demo-script entry
walking the OZ→NRC→subscriber→projection-api path and wire both into the MkDocs nav.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
