feat(acl): ACL skeleton — OpenZaak default-fill (refs #5) (#45)

services/acl/Acl.Application/AclService.cs

@@ -0,0 +1,20 @@
+namespace Acl.Application;
+
+/// <summary>The ACL's single operation: open a zaak from a domain payload,
+/// default-filling the ZGW-mandatory fields (ADR-0003).</summary>
+public sealed class AclService(IZaakGateway gateway, AclDefaults defaults, IClock clock)
+{
+    public Task<Uri> OpenZaakAsync(DomainRegistration registration, CancellationToken ct = default)
+    {
+        ArgumentNullException.ThrowIfNull(registration);
+
+        var request = new ZaakRequest(
+            defaults.Bronorganisatie,
+            defaults.VerantwoordelijkeOrganisatie,
+            defaults.Vertrouwelijkheidaanduiding,
+            defaults.ZaaktypeUrl,
+            clock.Today);
+
+        return gateway.OpenZaakAsync(request, ct);
+    }
+}