fix(tk2): rewards array uses ReceivedReward shape (reward_detail_id/item_type/is_usable)

The /retire and /finish responses carry two reward arrays with DIFFERENT
key schemas:

  rewards[]      → ReceivedReward(JsonData) parser
                   {reward_type, reward_detail_id, item_type, reward_count?, is_usable}
  reward_list[]  → PlayerStaticData.UpdateHaveUserGoodsNumByJsonData
                   {reward_type, reward_id, reward_num}

We were emitting both with reward_list's schema, so the client threw
KeyNotFoundException on `data["reward_detail_id"]` while parsing each
delta entry — observed live as the retire-screen failure.

- New TwoPickRewardReceivedDto mirrors the existing Achievement/
  TotalReceiveCountDto shape.
- FinishResponseDto.Rewards switched from List<RewardEntryDto>
  to List<TwoPickRewardReceivedDto>.
- GrantRunRewardsAndDeleteAsync pre-loads ItemEntry.Type for any
  Item-typed reward so item_type ships correctly (0 for currencies).
- Existing tests renamed RewardNum→RewardCount on the deltas list.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

SVSim.EmulatedEntrypoint/Services/ArenaTwoPickService.cs

@@ -297,13 +297,31 @@ public class ArenaTwoPickService : IArenaTwoPickService
         var rewardRows = await _rewards.GetRewardsByWinCountAsync(run.WinCount);
         var viewer = await LoadViewerForGrantsAsync(viewerId);
 
-        var deltas = new List<RewardEntryDto>();
+        // Pre-load item_type for any Item-typed reward so we can populate it on the
+        // per-grant delta entries. Currencies don't need a lookup (item_type stays 0).
+        var itemRewardIds = rewardRows
+            .Where(r => r.RewardType == (int)SVSim.Database.Enums.UserGoodsType.Item)
+            .Select(r => (int)r.RewardId)
+            .Distinct()
+            .ToList();
+        var itemTypeById = itemRewardIds.Count == 0
+            ? new Dictionary<int, int>()
+            : await _db.Items.Where(i => itemRewardIds.Contains(i.Id))
+                .ToDictionaryAsync(i => i.Id, i => i.Type);
+
+        var deltas = new List<TwoPickRewardReceivedDto>();
         foreach (var r in rewardRows)
         {
             var goodsType = (SVSim.Database.Enums.UserGoodsType)r.RewardType;
             await _grants.ApplyAsync(viewer, goodsType, r.RewardId, r.RewardNum);
-            // Rewards = deltas (per-grant amounts), not post-state totals.
-            deltas.Add(new RewardEntryDto { RewardType = r.RewardType, RewardId = r.RewardId, RewardNum = r.RewardNum });
+            deltas.Add(new TwoPickRewardReceivedDto
+            {
+                RewardType = r.RewardType,
+                RewardDetailId = r.RewardId,
+                RewardCount = r.RewardNum,
+                ItemType = itemTypeById.TryGetValue((int)r.RewardId, out var t) ? t : 0,
+                IsUsable = true,
+            });
         }
         await _db.SaveChangesAsync();