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/Controllers/LeaderSkinController.cs

@@ -139,7 +139,7 @@ public class LeaderSkinController : SVSimController
                     Status = rewardStatus,
                     Items = s.SetCompletionRewards.OrderBy(r => r.OrderIndex).Select(r => new SkinSeriesRewardItemDto
                     {
-                        RewardType = r.RewardType,
+                        RewardType = (int)r.RewardType,
                         RewardDetailId = r.RewardDetailId,
                         RewardNumber = r.RewardNumber,
                     }).ToList(),
@@ -203,14 +203,12 @@ public class LeaderSkinController : SVSimController
         }
 
         foreach (var r in product.Rewards.OrderBy(r => r.OrderIndex))
-            await tx.GrantAsync((UserGoodsType)r.RewardType, r.RewardDetailId, r.RewardNumber);
+            await tx.GrantAsync(r.RewardType, r.RewardDetailId, r.RewardNumber);
 
         var result = await tx.CommitAsync(HttpContext.RequestAborted);
         return new LeaderSkinBuyResponse
         {
-            RewardList = result.RewardList
-                .Select(g => new RewardListEntry { RewardType = g.RewardType, RewardId = g.RewardId, RewardNum = g.RewardNum })
-                .ToList(),
+            RewardList = result.RewardList.ToRewardList(),
         };
     }
 
@@ -260,15 +258,13 @@ public class LeaderSkinController : SVSimController
         foreach (var p in series.Products.OrderBy(p => p.Id))
         {
             foreach (var r in p.Rewards.OrderBy(r => r.OrderIndex))
-                await tx.GrantAsync((UserGoodsType)r.RewardType, r.RewardDetailId, r.RewardNumber);
+                await tx.GrantAsync(r.RewardType, r.RewardDetailId, r.RewardNumber);
         }
 
         var result = await tx.CommitAsync(HttpContext.RequestAborted);
         return new LeaderSkinBuyResponse
         {
-            RewardList = result.RewardList
-                .Select(g => new RewardListEntry { RewardType = g.RewardType, RewardId = g.RewardId, RewardNum = g.RewardNum })
-                .ToList(),
+            RewardList = result.RewardList.ToRewardList(),
         };
     }
 
@@ -298,7 +294,7 @@ public class LeaderSkinController : SVSimController
             return BadRequest(new { error = "series_not_completed" });
 
         foreach (var r in series.SetCompletionRewards.OrderBy(r => r.OrderIndex))
-            await tx.GrantAsync((UserGoodsType)r.RewardType, r.RewardDetailId, r.RewardNumber);
+            await tx.GrantAsync(r.RewardType, r.RewardDetailId, r.RewardNumber);
 
         _db.ViewerLeaderSkinSetClaims.Add(new ViewerLeaderSkinSetClaim
         {
@@ -310,9 +306,7 @@ public class LeaderSkinController : SVSimController
         var result = await tx.CommitAsync(HttpContext.RequestAborted);
         return new LeaderSkinBuyResponse
         {
-            RewardList = result.RewardList
-                .Select(g => new RewardListEntry { RewardType = g.RewardType, RewardId = g.RewardId, RewardNum = g.RewardNum })
-                .ToList(),
+            RewardList = result.RewardList.ToRewardList(),
         };
     }
 
@@ -362,7 +356,7 @@ public class LeaderSkinController : SVSimController
             },
             Rewards = p.Rewards.OrderBy(r => r.OrderIndex).Select(r => new SkinProductRewardDto
             {
-                RewardType = r.RewardType,
+                RewardType = (int)r.RewardType,
                 RewardDetailId = r.RewardDetailId,
                 RewardNumber = r.RewardNumber,
                 IsOwned = IsRewardOwned(r, ownedSkinIds),
@@ -379,7 +373,7 @@ public class LeaderSkinController : SVSimController
     private static bool IsRewardOwned(LeaderSkinShopProductRewardEntry r, IReadOnlySet<int> ownedSkinIds)
     {
         // Skin reward: direct check.
-        if (r.RewardType == (int)UserGoodsType.Skin)
+        if (r.RewardType == UserGoodsType.Skin)
             return ownedSkinIds.Contains((int)r.RewardDetailId);
         // Other types: we don't have the full cosmetic-owned graph in scope here. The product's
         // sibling Skin reward tells us whether the bundle was purchased; piggy-back on that by