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

services/acl/Acl.Application/IDefaultFillStore.cs

@@ -0,0 +1,14 @@
+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);
+}