test(acl): mutable default-fill store — update replaces current (refs #131)

services/acl/Acl.Application/DefaultFillSettings.cs

@@ -0,0 +1,10 @@
+namespace Acl.Application;
+
+/// <summary>The ZGW default-fill values a beheerder can edit at runtime (S-15b) — the mandatory fields
+/// the ACL stamps on every zaak (ADR-0003). The S-27 catalog-resolution keys (zaaktype identificatie,
+/// informatieobjecttype omschrijving) stay static config: editing them would desync the resolved-URL
+/// cache, and they're catalogus wiring rather than "default fill".</summary>
+public sealed record DefaultFillSettings(
+    string Bronorganisatie,
+    string VerantwoordelijkeOrganisatie,
+    string Vertrouwelijkheidaanduiding);

services/acl/Acl.Application/IDefaultFillStore.cs

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+namespace Acl.Application;
+
+/// <summary>Holds the ACL's current default-fill values, editable at runtime through the beheer portal
+/// (S-15b). Seeded from config at startup.
+///
+/// ponytail: in-memory only — an edit is lost on restart, when it reverts to the configured env
+/// (ADR-0026). Adequate for the reference demo; back it with a DB if durable, audited config is needed.
+/// </summary>
+public interface IDefaultFillStore
+{
+    DefaultFillSettings Current { get; }
+
+    void Update(DefaultFillSettings settings);
+}

services/acl/Acl.Application/InMemoryDefaultFillStore.cs

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+namespace Acl.Application;
+
+/// <summary>In-memory <see cref="IDefaultFillStore"/> (ADR-0026), seeded from config. Thread-safe: the
+/// hosted worker reads <see cref="Current"/> per zaak while the beheer endpoint may update it.</summary>
+public sealed class InMemoryDefaultFillStore(DefaultFillSettings seed) : IDefaultFillStore
+{
+    private readonly object _gate = new();
+    private DefaultFillSettings _current = seed;
+
+    public DefaultFillSettings Current
+    {
+        get { lock (_gate) return _current; }
+    }
+
+    public void Update(DefaultFillSettings settings)
+    {
+        // ponytail: red stub — real assignment lands in the green commit.
+    }
+}