feat(db): add gacha-point balance + received tables

SVSim.Database/Models/Viewer.cs

@@ -65,6 +65,10 @@ public class Viewer : BaseEntity<long>
 
     public List<ViewerPackOpenCount> PackOpenCounts { get; set; } = new List<ViewerPackOpenCount>();
 
+    public List<ViewerGachaPointBalance> GachaPointBalances { get; set; } = new List<ViewerGachaPointBalance>();
+
+    public List<ViewerGachaPointReceived> GachaPointReceived { get; set; } = new List<ViewerGachaPointReceived>();
+
     public List<ViewerBuildDeckProductPurchase> BuildDeckPurchases { get; set; } = new List<ViewerBuildDeckProductPurchase>();
 
     public List<ViewerMission> Missions { get; set; } = new List<ViewerMission>();

SVSim.Database/Models/ViewerGachaPointBalance.cs

@@ -0,0 +1,17 @@
+using Microsoft.EntityFrameworkCore;
+
+namespace SVSim.Database.Models;
+
+/// <summary>
+/// Per-viewer, per-pack gacha-point balance. Owned collection on <see cref="Viewer"/>.
+/// <c>PackId</c> = parent_gacha_id. <c>Points</c> accumulates one per pack opened (or
+/// <c>PackChildGachaEntry.OverrideIncreaseGachaPoint</c> when set on the child) and is
+/// decremented by <see cref="PackGachaPointConfig.ExchangeablePoint"/> per exchange.
+/// Unique index on (ViewerId, PackId) per feedback_owned_collection_unique_index.
+/// </summary>
+[Owned]
+public class ViewerGachaPointBalance
+{
+    public int PackId { get; set; }
+    public int Points { get; set; }
+}

SVSim.Database/Models/ViewerGachaPointReceived.cs

@@ -0,0 +1,17 @@
+using Microsoft.EntityFrameworkCore;
+
+namespace SVSim.Database.Models;
+
+/// <summary>
+/// Marker row recording that a viewer has already redeemed <c>CardId</c> from <c>PackId</c>'s
+/// gacha-point exchange. Drives the per-entry <c>is_received</c> flag in
+/// <c>/pack/get_gacha_point_rewards</c>. Owned collection on <see cref="Viewer"/>.
+/// Unique index on (ViewerId, PackId, CardId) per feedback_owned_collection_unique_index.
+/// </summary>
+[Owned]
+public class ViewerGachaPointReceived
+{
+    public int PackId { get; set; }
+    public long CardId { get; set; }
+    public DateTime ReceivedAt { get; set; }
+}