Pack logic cleanup

SVSim.Database/Models/ShadowverseCardEntry.cs

@@ -32,6 +32,14 @@ public class ShadowverseCardEntry : BaseEntity<long>
     /// </summary>
     public Rarity Rarity { get; set; }
 
+    /// <summary>
+    /// True for foil/animated card rows (cards.json `is_foil=1`). Foils live in the same
+    /// CardSet as their non-foil twin (twin's card_id = this.Id - 1). Excluded from pack
+    /// draw pools by DbCardPoolProvider; reached via the per-card animated-upgrade roll
+    /// in PackOpenService.
+    /// </summary>
+    public bool IsFoil { get; set; }
+
     #region Owned
 
     /// <summary>