feat: user tombstone and retired usernames

crates/domain/tests/testing/in_memory_store_test.rs

@@ -575,3 +575,56 @@ async fn deleting_a_review_while_another_remains_keeps_the_movie_and_records_one
     assert_eq!(store.movie_count(), 1);
     assert_eq!(store.recorded_events().len(), 1);
 }
+
+#[tokio::test]
+async fn fake_mark_deleted_mirrors_the_sqlite_tombstone() {
+    let store = InMemoryStore::new();
+    let user = test_user("ghost");
+    let other = test_user("other");
+    UserRepository::save(&*store, &user).await.unwrap();
+    UserRepository::save(&*store, &other).await.unwrap();
+    RefreshSessionRepository::create(
+        &*store,
+        &RefreshSession {
+            id: Uuid::new_v4(),
+            user_id: user.id().clone(),
+            token: "t".into(),
+            expires_at: Utc::now(),
+            created_at: Utc::now(),
+        },
+    )
+    .await
+    .unwrap();
+    let event = domain::events::DomainEvent::UserDeleted {
+        user_id: user.id().clone(),
+    };
+
+    store
+        .mark_deleted(user.id(), std::slice::from_ref(&event))
+        .await
+        .unwrap();
+
+    assert!(store.find_by_id(user.id()).await.unwrap().is_none());
+    assert!(store.find_by_email(user.email()).await.unwrap().is_none());
+    assert!(
+        store
+            .find_by_username(user.username())
+            .await
+            .unwrap()
+            .is_none()
+    );
+    assert_eq!(store.list_with_stats().await.unwrap().len(), 1);
+    assert!(
+        store
+            .find_tombstoned_by_id(user.id())
+            .await
+            .unwrap()
+            .is_some()
+    );
+    assert!(store.is_username_retired(user.username()).await.unwrap());
+    let upper =
+        domain::value_objects::Username::new(user.username().value().to_uppercase()).unwrap();
+    assert!(store.is_username_retired(&upper).await.unwrap());
+    assert_eq!(store.refresh_session_count(), 0);
+    assert_eq!(store.recorded_events().len(), 1);
+}