## What & why
Before this change the self-service confirmation and the openbaar register showed **different** identifiers, so a citizen could not look their registration back up (#78). Now both surface the same **reference**:
- **domain → ACL (write):** the domain `registrationId` is set as the zaak's `identificatie` on `POST /zaken`.
- **event-subscriber → ACL (read):** the subscriber reads the zaak's `identificatie` back through the ACL (§8.1 — only the ACL talks to ZGW) via a new `POST /zaken/reference`, and stores it on the projection row **and** the `processed_notifications` replay log.
- **BFF + openbaar:** the public view exposes `id/status/reference` (never bsn/naam) and searches by id or reference; the register's "Referentie" column shows the reference.
Storing the reference in the replay log keeps ADR-0008's **rebuild-is-log-only** invariant intact — `/admin/rebuild` reproduces the reference without re-reading the ACL.
Decision recorded in **ADR-0012**.
## Definition of Done
- [x] Linked issue: #78
- [x] Tests written first; red → green per layer
- [x] Unit + acceptance green (`make unit`): domain 49, acl 27, bff 20, event-subscriber 19, acceptance 7
- [x] Frontend lint + test green (`nx run-many -t lint test`)
- [x] Mutation ≥ break(90): acl 100%, event-subscriber 100%, bff 100%, domain 98.41% (pre-existing FlowableWorkflowClient baseline, untouched)
- [x] e2e extended: confirmation reference == register reference
- [x] openapi.json + api-client regenerated (drift guard green)
- [x] ADR-0012 added; demo-script note appended
- [x] `Acl__BaseUrl` wired for the subscriber in compose
closes#78
Reviewed-on: #79
Add the projection persistence and the two services around it:
- Projection.ReadModel: a shared EF Core (Npgsql) read model owning the projection
schema — register_projection + the subscriber's processed_notifications log — plus
EfProjectionStore / EfNotificationLog (atomic record-or-skip on the PK for idempotency)
and the initial migration. One rebuildable store, written by the subscriber and read
by projection-api (ADR-0008).
- EventSubscriber.Api: POST /notifications NRC callback (enforces the abonnement bearer,
401 without it per ADR-0007), POST /admin/rebuild, /health. Migrates on start.
- ProjectionApi.Api: GET /register, GET /register/{id}, /health — the read side.
dotnet-ef pinned as a local tool for migrations; NuGetAuditMode=direct so EF's
design-time-only tooling transitive doesn't flag the shipped build.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
