feat(domain): ProvideDocuments stores the diploma via the ACL then completes the wait (refs #103)

IAclClient.StoreDiplomaAsync + AclHttpClient (base64 JSON to the ACL /documenten
endpoint). ProvideDocuments stores the uploaded bytes against the zaak (when opened)
before completing WachtOpDocumenten; the domain endpoint accepts the file base64-encoded.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

services/domain/Big.Application/Ports.cs

@@ -52,6 +52,13 @@ public interface IAclClient
     /// the zaak's final status — which OpenZaak notifies over NRC; the domain never names statustypen.
     /// </summary>
     Task ApproveZaakAsync(Uri zaakUrl, CancellationToken ct = default);
+
+    /// <summary>
+    /// Store an uploaded diploma against the zaak (S-10b). The domain hands over the zaak, the raw file
+    /// bytes, and the file's name/type; the ACL creates the ZGW informatieobject and relates it to the
+    /// zaak (§8.1). Returns the stored document's URL.
+    /// </summary>
+    Task<Uri> StoreDiplomaAsync(Uri zaakUrl, byte[] content, string fileName, string contentType, CancellationToken ct = default);
 }
 
 /// <summary>

services/domain/Big.Application/ProvideDocuments.cs

@@ -2,10 +2,12 @@ using Big.Domain;
 
 namespace Big.Application;
 
-/// <summary>A zorgprofessional's signal that they have supplied the documents their registration is
-/// waiting for ("documenten aanleveren"). <paramref name="Bsn"/> is the authenticated caller (from the
-/// DigiD token, forwarded by the BFF): only the registration's own bsn may provide its documents.</summary>
-public sealed record ProvideDocumentsCommand(RegistrationId RegistrationId, string Bsn);
+/// <summary>A zorgprofessional's upload of the diploma their registration is waiting for ("documenten
+/// aanleveren"). <paramref name="Bsn"/> is the authenticated caller (from the DigiD token, forwarded by
+/// the BFF): only the registration's own bsn may provide its documents. <paramref name="Content"/> is
+/// the raw file, with its <paramref name="FileName"/> and <paramref name="ContentType"/>.</summary>
+public sealed record ProvideDocumentsCommand(
+    RegistrationId RegistrationId, string Bsn, byte[] Content, string FileName, string ContentType);
 
 /// <summary>The outcome of a provide-documents request.</summary>
 public enum ProvideDocumentsOutcome
@@ -19,14 +21,14 @@ public enum ProvideDocumentsOutcome
 }
 
 /// <summary>
-/// The provide-documents use case (S-10a): a zorgprofessional supplies the documents their registration
-/// is parked waiting for, completing the WachtOpDocumenten task so the registratie process leaves the
-/// 30-day wait and continues to beoordeling (ADR-0017). Owner-scoped by bsn. Completing the wait is
-/// best-effort: if the registration never started a process (or already left the wait), the request
-/// still stands, mirroring how <see cref="WithdrawRegistration"/> cancels best-effort. The actual file
-/// upload and its ZGW storage via the ACL is S-10b; this is the trigger that unblocks the process.
+/// The provide-documents use case (S-10a/S-10b): a zorgprofessional uploads the diploma their
+/// registration is parked waiting for. The document is stored in ZGW via the ACL (§8.1), then the
+/// WachtOpDocumenten task is completed so the registratie process leaves the 30-day wait and continues
+/// to beoordeling (ADR-0017). Owner-scoped by bsn. Both steps are best-effort about missing preconditions
+/// (mirroring <see cref="WithdrawRegistration"/>): storage needs an opened zaak, and completion needs a
+/// running process — a request that arrives before either still stands, storing/completing what it can.
 /// </summary>
-public sealed class ProvideDocuments(IRegistrationStore store, IWorkflowClient workflow)
+public sealed class ProvideDocuments(IRegistrationStore store, IWorkflowClient workflow, IAclClient acl)
 {
     public async Task<ProvideDocumentsOutcome> HandleAsync(ProvideDocumentsCommand command, CancellationToken ct = default)
     {
@@ -38,6 +40,11 @@ public sealed class ProvideDocuments(IRegistrationStore store, IWorkflowClient w
         if (registration is null || registration.Bsn != command.Bsn)
             return ProvideDocumentsOutcome.NotFound;
 
+        // Store the diploma against the zaak (once it is opened) — the ACL is the only ZGW caller (§8.1).
+        if (registration.ZaakUrl is not null)
+            await acl.StoreDiplomaAsync(
+                registration.ZaakUrl, command.Content, command.FileName, command.ContentType, ct);
+
         // Complete the document wait (if a process is running) so beoordeling can proceed.
         if (registration.ProcessInstanceId is not null)
             await workflow.CompleteDocumentWaitAsync(registration.ProcessInstanceId, ct);