Prebuilt deck purchasing and fixes

SVSim.Database/Models/BuildDeckSeriesEntry.cs

@@ -0,0 +1,22 @@
+using SVSim.Database.Common;
+
+namespace SVSim.Database.Models;
+
+/// <summary>
+/// One prebuilt-deck series ("Structure Deck Set 7", "Trial 19", etc.). PK = wire series_id.
+/// IsEnabled gates whether /build_deck/info renders this series — disabled rows are placeholder
+/// stubs created from the client CSV until we capture a /info response that enriches them.
+/// </summary>
+public class BuildDeckSeriesEntry : BaseEntity<int>
+{
+    public int OrderIndex { get; set; }   // wire order_id; controls display order
+    public string NameKey { get; set; } = string.Empty;      // BDSSN_*
+    public string IntroKey { get; set; } = string.Empty;     // BDSI_*
+    public string TitlePath { get; set; } = string.Empty;
+    public string DrumrollPath { get; set; } = string.Empty;
+    public bool IsNew { get; set; }
+    public bool IsEnabled { get; set; }
+
+    public List<BuildDeckSeriesRewardEntry> SeriesRewards { get; set; } = new();
+    public List<BuildDeckProductEntry> Products { get; set; } = new();
+}