DB Cleanup

SVSim.Database/SVSimDbContext.cs

@@ -126,6 +126,21 @@ public class SVSimDbContext : DbContext
         modelBuilder.Entity<PackConfigEntry>().OwnsMany(p => p.Banners);
         modelBuilder.Entity<Viewer>().OwnsMany(v => v.PackOpenCounts);
 
+        // OwnedCardEntry and OwnedItemEntry use composite PK (ViewerId, Id) where Id is auto-
+        // generated, which silently permits multiple rows per (Viewer, Card) or (Viewer, Item).
+        // The intended semantic is one row per pair with Count as multiplicity — enforce that as
+        // a unique index so any future find-or-add that forgets to .Include the collection (and
+        // therefore re-creates a row that already exists in the DB) crashes loudly at SaveChanges
+        // instead of silently duplicating ownership rows.
+        modelBuilder.Entity<Viewer>().OwnsMany(v => v.Cards, b =>
+        {
+            b.HasIndex("ViewerId", "CardId").IsUnique();
+        });
+        modelBuilder.Entity<Viewer>().OwnsMany(v => v.Items, b =>
+        {
+            b.HasIndex("ViewerId", "ItemId").IsUnique();
+        });
+
         modelBuilder.Entity<CardCosmeticReward>(b =>
         {
             b.HasKey(r => new { r.CardId, r.Type, r.CosmeticId });