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/Services/MissionAssembler.cs

@@ -92,7 +92,7 @@ public sealed class MissionAssembler : IMissionAssembler
                 LotType = cat.LotType.ToString(),
                 BattlePassPoint = cat.BattlePassPoint.ToString(),
                 RequireNumber = cat.RequireNumber,
-                RewardType = cat.RewardType,
+                RewardType = (int)cat.RewardType,
                 RewardDetailId = cat.RewardDetailId,
                 RewardNumber = cat.RewardNumber,
                 DefaultFlag = cat.DefaultFlag,
@@ -117,7 +117,7 @@ public sealed class MissionAssembler : IMissionAssembler
                 TotalCount = total,
                 AchievementName = catalog.Name,
                 RequireNumber = catalog.RequireNumber,
-                RewardType = catalog.RewardType,
+                RewardType = (int)catalog.RewardType,
                 RewardDetailId = catalog.RewardDetailId,
                 RewardNumber = catalog.RewardNumber,
                 MaxLevel = maxLevel,
@@ -164,7 +164,7 @@ public sealed class MissionAssembler : IMissionAssembler
                     {
                         entry.RewardInfo = new BPMonthlyMissionRewardInfoDto
                         {
-                            RewardType = mm.RewardType.Value.ToString(),
+                            RewardType = ((int)mm.RewardType.Value).ToString(),
                             RewardDetailId = (mm.RewardDetailId ?? 0).ToString(),
                             RewardNumber = (mm.RewardNumber ?? 0).ToString(),
                         };