refactor: type reward_type columns as UserGoodsType enum

Replace bare `int RewardType` on 12 catalog/reward entities and GrantedReward
with the existing UserGoodsType enum. Verified against the decompiled client:
every wire reward_type decodes through the single Wizard.UserGoods.Type enum, so
one enum is correct across all endpoint families (item_type is a separate
Item.Type axis, left untouched). EF stores the enum as the same int column, so
there is no migration.

- Importers cast seed int -> UserGoodsType at the ingest boundary.
- New GrantedReward.ToRewardList() extension replaces 8 copy-pasted
  GrantedReward -> RewardListEntry projections.
- Fix 3 .ToString() sites that would otherwise emit enum names ("Crystal")
  instead of the int wire value ("2").
- Wire DTOs keep int; the enum is widened to int at the wire boundary only.

Build green; 962/962 tests pass.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

SVSim.EmulatedEntrypoint/Models/Dtos/RewardListExtensions.cs

@@ -0,0 +1,21 @@
+using SVSim.Database.Services;
+
+namespace SVSim.EmulatedEntrypoint.Models.Dtos;
+
+/// <summary>
+/// Projects inventory <see cref="GrantedReward"/> results (post-state totals or per-grant deltas)
+/// into the wire <see cref="RewardListEntry"/> shape. The <c>reward_type</c> enum is widened to its
+/// int wire value at this single boundary. Replaces the per-endpoint copies of this projection
+/// (pack/open, leader_skin/buy*, build_deck/buy, sleeve/buy, item_purchase, spot_card_exchange,
+/// gacha-point exchange).
+/// </summary>
+public static class RewardListExtensions
+{
+    public static List<RewardListEntry> ToRewardList(this IEnumerable<GrantedReward> grants) =>
+        grants.Select(g => new RewardListEntry
+        {
+            RewardType = (int)g.RewardType,
+            RewardId = g.RewardId,
+            RewardNum = g.RewardNum,
+        }).ToList();
+}