docs(backlog): add WP-53 (identity seam + citizen-scoping) and WP-54 (OpenZaak harness)

The two highest-value OpenZaak roadmap gaps, each written self-contained (a "current
state" handoff section) so a fresh session can execute from the file + repo alone:

- WP-53: replace the stubbed owner/BSN with a real per-request CallerIdentity
  (pluggable stub, not DigiD), threading it into Authz, the ZGW JWT user claims, and
  a citizen-scoped read (rol__…__inpBsn). Production-blocking for a real deployment.
- WP-54: a separate docker-compose OpenZaak + scripted bootstrap + opt-in
  Category=Integration test — makes 50/51/52 developable against a live instance
  instead of only fixtures; kept out of the default gate.

Indexed in the backlog README (rows + phase-9 ordering note) and cited from
openzaak-integration.md.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docs/project/backlog/WP-54-openzaak-integration-harness.md

@@ -0,0 +1,114 @@
+# WP-54 — Docker OpenZaak integration-test harness
+
+Status: todo
+Phase: 9 — OpenZaak / ZGW integration
+
+## Why
+
+Everything ZGW so far is verified against **fixtures + a stub `HttpMessageHandler`** — nothing
+exercises a real OpenZaak. That is fine for unit-testing the mapper/JWT/pagination, but it does
+not prove the BFF actually talks to OpenZaak (auth accepted, real response shapes, real
+pagination, zaaktype resolution). This WP stands up a **local OpenZaak via docker**, seeds a
+minimal catalog + a client credential matching `ZgwOptions`, and adds an **opt-in** integration
+test that points the BFF at it with `Zgw:Enabled=true`. It closes the "no live instance" gap
+called out in the roadmap and makes WP-50/51/52 developable against something real.
+
+## Context — current state (read before designing; self-contained handoff)
+
+- **What exists to test**: `backend/src/BigRegister.Api/Zgw/OpenZaakZaakSource.cs` (lists zaken,
+  follows `{count,next,previous,results}`, resolves zaaktype labels from Catalogi, Bearer auth
+  via `ZgwTokenProvider`), selected when `Zgw:Enabled=true`. Config is the `Zgw` section of
+  `appsettings.json` (`ZrcBaseUrl`, `ZtcBaseUrl`, `ClientId`, `Secret`, `UserId`,
+  `UserRepresentation`) → `Zgw/ZgwOptions.cs`.
+- **Current tests** (the pattern to extend, not replace): `ZgwZaakMapperTests` (inline JSON),
+  `OpenZaakZaakSourceTests` (stub handler). These stay as fast unit tests; the new integration
+  test is a **separate, opt-in** category so the default `dotnet test` and CI stay fast/offline.
+- **Existing compose**: repo root `docker-compose.yml` runs FE + BFF only (Swagger at :5000).
+  Do **not** bolt OpenZaak onto it — OpenZaak is heavy (postgres + redis + celery). Use a
+  **separate** compose file so `docker compose up` stays light for everyone else.
+- **Test project**: `backend/tests/BigRegister.Tests/` (xunit). It uses
+  `Microsoft.AspNetCore.Mvc.Testing` (`TestWebApplicationFactory.cs`) — the factory can be
+  configured to override the `Zgw` config section to point at the compose instance.
+- **CLAUDE.md / backlog GREEN**: the default local gate and CI must remain runnable without
+  docker/OpenZaak. Anything requiring the harness is explicitly separate (like e2e is today —
+  a distinct job, not chained into `npm run ci`).
+
+OpenZaak facts that shape the harness (from the ZGW research):
+
+- OpenZaak is the reference impl of the 5 ZGW APIs; the published
+  `docker-compose.yml` (github.com/open-zaak/open-zaak) brings up **openzaak (web + celery),
+  postgres, redis** and (optionally) Open Notificaties. A one-time **bootstrap** is required:
+  create a superuser, register an **Application** in the Autorisaties API with a **Client
+  ID/Secret + scopes** (`zaken.lezen`, `catalogi.lezen`, …), and import/create a **Catalogus
+  with a zaaktype** (published) so there is something to read.
+- Auth = the HS256 JWT the BFF already mints; the harness's client credentials must **match**
+  `ZgwOptions.ClientId`/`Secret`.
+- Reading a zaak needs read scope on **both** Zaken and Catalogi (zaaktype resolution).
+
+## Read first
+
+- [openzaak-integration.md](../reference/openzaak-integration.md) (the seam + config keys).
+- [ADR-0005](../reference/architecture/0005-openzaak-behind-bff.md).
+- WP-19 (`WP-19-e2e-smoke.md`) — the precedent for a heavy, separate, opt-in test job (mirror
+  its "not chained into the default gate" structure).
+- Upstream: OpenZaak docker docs (https://open-zaak.readthedocs.io/) + the repo's
+  `docker-compose.yml` and its `import` fixtures for a demo catalogus.
+
+## Decisions (pre-made, don't relitigate)
+
+- **Separate compose file** (e.g. `backend/openzaak/docker-compose.openzaak.yml`), never merged
+  into the root compose. `docker compose up` stays FE+BFF only.
+- **Opt-in test category.** Tag the integration test `[Trait("Category", "Integration")]`;
+  exclude it from the default run (`dotnet test --filter Category!=Integration`) and from the
+  standard CI jobs. Provide a documented command / optional manual CI job to run it.
+- **Bootstrap is scripted, not manual.** A checked-in setup (compose `import` fixture or a small
+  bootstrap script) creates the client credentials (matching `ZgwOptions`), a catalogus, and one
+  published zaaktype + one zaak — so the test is deterministic and repeatable.
+- **Provider stays stubbed** (WP-53) — this WP is about the ZGW round-trip, not real user auth.
+
+## Files
+
+- New: `backend/openzaak/docker-compose.openzaak.yml` + bootstrap fixture/script + a short
+  `backend/openzaak/README.md` (how to bring it up, credentials, teardown).
+- New: `backend/tests/BigRegister.Tests/OpenZaakIntegrationTests.cs` (Category=Integration):
+  configure the BFF (`WebApplicationFactory`) with `Zgw:Enabled=true` + the compose URLs/creds,
+  hit `/admin/cases`, assert the seeded zaak comes back mapped.
+- Edit: `docs/reference/openzaak-integration.md` (add a "Run against real OpenZaak" section);
+  optionally a manual/gated CI job in `.github/workflows/ci.yml` mirroring the e2e job's shape.
+
+## Steps
+
+1. Add the separate compose file bringing up OpenZaak + postgres + redis; pin image versions.
+2. Script the bootstrap: superuser, Autorisaties Application (Client ID/Secret = `ZgwOptions`),
+   a catalogus + one published zaaktype + one zaak with a natuurlijk-persoon rol (the seeded BSN).
+3. Write the opt-in integration test: point the BFF at the compose instance, assert the mapped
+   zaak (id = uuid, type = zaaktype label, status) via `/admin/cases`.
+4. Document `docker compose -f … up` + the run command; optionally add a manual CI job.
+
+## Acceptance criteria
+
+- [ ] `docker compose -f backend/openzaak/docker-compose.openzaak.yml up` yields a reachable
+      OpenZaak with the seeded catalogus + zaak, and credentials matching `ZgwOptions`.
+- [ ] The Category=Integration test passes against it; the BFF returns the seeded zaak mapped to
+      `ApplicationSummaryDto` through the real HTTP + JWT path.
+- [ ] Default `dotnet test` and `npm run ci` are unaffected (integration test excluded, no docker
+      needed); `docker compose up` (root) is unchanged.
+
+## Verification
+
+`docker compose -f backend/openzaak/docker-compose.openzaak.yml up -d` →
+`dotnet test --filter Category=Integration` → green; then teardown.
+
+## Out of scope
+
+Documenten/DRC + Notificaties services in the harness (add when WP-51/52 land), a permanent
+always-on CI job (keep it opt-in/manual — OpenZaak startup is slow), performance testing.
+
+## Risks
+
+- OpenZaak startup is slow + resource-heavy → keep it opt-in; a permanent CI job would blow the
+  same runner budget WP's storybook cap just fixed.
+- ZGW API/version drift vs the pinned image can change response shapes → pin image versions and
+  keep the fixture in the repo.
+- Bootstrap client scopes must include `catalogi.lezen` or zaaktype resolution 403s — cover in
+  the setup script.