Deck list work

SVSim.Database/Models/SpecialDeckFormatEntry.cs

@@ -0,0 +1,17 @@
+using SVSim.Database.Common;
+
+namespace SVSim.Database.Models;
+
+/// <summary>
+/// One entry from /mypage/index data.room_type_in_session.special_deck_format_list. A list of deck-format
+/// codes that have a current "special" window (e.g. format "5" valid until 2030-06-26). Id is a synthetic
+/// ordinal — the wire has no explicit identifier, and ImportRoomTypeInSession follows the same clear-and-
+/// rewrite pattern as ImportBanners.
+/// </summary>
+public class SpecialDeckFormatEntry : BaseEntity<int>
+{
+    /// <summary>Wire is string per prod's PHP convention even though it looks numeric (e.g. "5").</summary>
+    public string DeckFormat { get; set; } = string.Empty;
+
+    public DateTime EndTime { get; set; }
+}