Fix SQLite crash: don't ORDER BY DateTimeOffset

SQLite can't translate ORDER BY on DateTimeOffset columns, so loading the
wishlists/invites pages threw NotSupportedException. Order by the autoincrement
Id (same newest-first result) instead. Add a regression test that exercises the
owned/shared list queries against SQLite.

Co-Authored-By: Claude Opus 4.8 <[email protected]>

tests/WishNinja.Tests/WishlistServiceTests.cs

@@ -144,5 +144,17 @@ public class WishlistServiceTests : IDisposable
         Assert.NotNull(await _svc.GetDetailAsync(1, OwnerId));    // owner always
     }
 
+    [Fact]
+    public async Task Owned_and_shared_list_queries_run_on_sqlite()
+    {
+        // Regression: these order by a timestamp; SQLite can't ORDER BY DateTimeOffset, so the
+        // service must order by a supported column. This would throw NotSupportedException otherwise.
+        var owned = await _svc.GetOwnedAsync(OwnerId);
+        Assert.Single(owned);
+
+        var shared = await _svc.GetSharedWithAsync(FriendId);
+        Assert.Single(shared); // the AllMembers list is visible to other members
+    }
+
     public void Dispose() => _db.Dispose();
 }