feat(acl,domain): cancel the ZGW zaak on document-timeout expiry (S-10c, closes #106) (#109)

## S-10c · Close the ZGW zaak on document-timeout expiry (closes #106)

Completes the S-10a/S-10b boundary flagged in ADR-0017: when a registration's 30-day document term lapses, the domain now cancels the **ZGW zaak** as well as marking the aggregate `Verlopen`, so OpenZaak and the register no longer diverge.

### What it does
On expiry the `ExpireRegistrationWorker` calls the ACL to set the zaak to a distinct, non-terminal **`Geannuleerd`** status with a **`Vervallen`** resultaat (vs the approval `Afgehandeld` + `Geregistreerd`), resolved **by omschrijving** in the ACL — the ACL-first ordering mirrors approval so a failed ZGW call leaves the job for redelivery rather than diverging the two.

**Path:** Flowable P30D timer → `RegistratieVerlopen` job → domain `ExpireRegistrationWorker` → ACL `POST /annuleringen` → ZGW `resultaten` + `statussen` (Geannuleerd) → aggregate `Verlopen`.

### Layers touched (each red→green)
- **ACL gateway** — `SetZaakToCancellationStatusAsync` (Geannuleerd + Vervallen by name); approval now resolves its `Geregistreerd` resultaat by name too (a second resultaattype now exists).
- **ACL service/API** — `AclService.CancelZaakAsync` + `POST /annuleringen`.
- **Domain** — `IAclClient.CancelZaakAsync` + client; expiry worker cancels the zaak before advancing to `Verlopen`, guarded against redelivery double-cancel.
- **Seed** — non-terminal `Geannuleerd` statustype (volgnummer 2; `Afgehandeld` → 3) + `Vervallen` resultaattype, both idempotent by omschrijving and sharing the zaaktype's procestype.
- **Verify/integration** — ACL↔OpenZaak integration test (live `Geannuleerd` + resultaat); `run-domain-check.sh` fires the real P30D timer and asserts the zaak reaches `Geannuleerd` end-to-end; BDD scenario asserts cancel-on-timeout vs untouched-when-in-time.
- **Docs** — ADR-0019 (cancellation modelling decision), demo-script, BACKLOG.

### Design note (ADR-0019)
ZGW allows only one eindstatus per zaaktype, so `Geannuleerd` is modelled as a **non-terminal** status (it records a cancellation status + resultaat but does not set `einddatum`). This follows the issue's explicit "distinct statustype + resultaat" outcome; the shared-eindstatus alternative is recorded in the ADR.

### Tests
Unit + acceptance all green locally (Acl 38, Big 134, Acceptance 17, Bff 33, EventSubscriber 19). Integration + verify-stack run in CI (need live OpenZaak + selectielijst egress).

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Reviewed-on: #109

services/acl/Acl.IntegrationTests/OpenZaakGatewayIntegrationTests.cs

@@ -75,6 +75,39 @@ public sealed class OpenZaakGatewayIntegrationTests(OpenZaakFixture stack)
         Assert.Equal(eindstatustype.ToString(), status.GetProperty("statustype").GetString());
     }
 
+    [Fact]
+    public async Task Cancelling_a_zaak_records_the_geannuleerd_status_and_a_resultaat()
+    {
+        var zaaktype = await stack.FindPublishedBigZaaktypeAsync();
+        Assert.True(zaaktype is not null,
+            "No published BIG-REGISTRATIE zaaktype found in OpenZaak — bring the stack up and " +
+            "seed it with OZ_PUBLISH=1 (`make integration` does this).");
+
+        var gateway = new OpenZaakGateway(stack.Http, stack.Options);
+        var zaakUrl = await gateway.OpenZaakAsync(new ZaakRequest(
+            Bronorganisatie: "517439943",
+            VerantwoordelijkeOrganisatie: "517439943",
+            Vertrouwelijkheidaanduiding: "openbaar",
+            Zaaktype: zaaktype!,
+            Startdatum: DateOnly.FromDateTime(DateTime.UtcNow),
+            Identificatie: Guid.NewGuid().ToString()));
+
+        await gateway.SetZaakToCancellationStatusAsync(zaakUrl, zaaktype!, DateOnly.FromDateTime(DateTime.UtcNow));
+
+        // The zaak's current status is the Geannuleerd statustype — distinct from the approval eindstatus.
+        var zaak = await stack.GetZaakAsync(zaakUrl);
+        var statusUrl = zaak.GetProperty("status").GetString();
+        Assert.False(string.IsNullOrEmpty(statusUrl), "the cancelled zaak has no current status");
+
+        var status = await stack.GetJsonAsync(new Uri(statusUrl!));
+        var geannuleerd = await stack.FindStatustypeByOmschrijvingAsync(zaaktype!, "Geannuleerd");
+        Assert.Equal(geannuleerd.ToString(), status.GetProperty("statustype").GetString());
+
+        // ...and a resultaat is recorded (OpenZaak requires it before a closing/terminal status).
+        Assert.False(string.IsNullOrEmpty(zaak.GetProperty("resultaat").GetString()),
+            "the cancelled zaak has no resultaat");
+    }
+
     [Fact]
     public async Task Storing_a_diploma_creates_a_real_informatieobject_related_to_the_zaak()
     {