Red — BeoordeelRegistratie has no user-task dependency and doesn't complete the task.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
## What & why
First sub-slice of **S-12 (#13)** — the **beoordeling decision model** in the Domain Service. Foundation for the behandel-portal: it gives the domain a proper decision lifecycle before any UI/Flowable/BFF work.
- **Statuses:** add `InBehandeling` and `Afgewezen` to `RegistrationStatus`.
- **Aggregate:** `TakeIntoBehandeling()` (`Ingediend → InBehandeling`, idempotent, guards terminal states); generalise the behandelaar decision — `Approve()` (requires a zaak) and new `Reject()` both act on an `Ingediend`/`InBehandeling` registration → `Ingeschreven`/`Afgewezen`.
- **Use-case:** `BeoordeelRegistratie` (`goedkeuren` sets the zaak's final status via the ACL §8.1 → `Ingeschreven`; `afwijzen` → `Afgewezen`, domain-only for now). Idempotent.
- **Endpoint:** `POST /registrations/{id}/decide` (`{ "besluit": "goedkeuren" | "afwijzen" }`), superseding the temporary `/approve` (retired when the portal lands, S-12d).
- **BDD:** `EenRegistratieBeoordelen.feature` — goedkeuren + afwijzen scenarios (feature-scoped bindings).
**Scoped out** to later S-12 sub-slices: Flowable user-task claim/complete + BPMN `userTask` (S-12b), BFF `/behandel/*` + medewerker authz (S-12c), the Angular behandel-portal + e2e (S-12d), and propagating a *rejection* to the zaak/projection via the ACL.
## Definition of Done
- [x] Linked issue: #13 (umbrella; this PR `refs`, does not close)
- [x] Tests first; red → green per behaviour
- [x] Unit + acceptance green (`make unit`): domain 65, acceptance 9
- [x] Mutation ≥ break(90): domain 98.77%, no survivors in new code (the one unkilled mutant is the pre-existing `FlowableWorkflowClient` baseline)
- [ ] CI green (pending)
Part of #13.
Reviewed-on: #82
