fix(pack): tutorial flow display + open end-to-end

Four targeted fixes that together let /tutorial/pack_info display
the legendary starter at index 0, let /tutorial/pack_open succeed
on it, and let the pack drop out of the shop after.

1. /pack/info now loads viewer.Items into a Dictionary<long,int>
   and threads it through ToDto so child_gacha_info.item_number
   reflects the viewer's actual owned count of item_id. Previously
   defaulted to 0 for every pack, so the legendary pack 99047
   reported item_number=0 immediately after the gift granted 1×
   ticket id=90001. Verified against the prod tutorial capture.

2. PackRepository.GetActivePacks now orders parent_gacha_id DESC
   to match prod's /pack/info wire order (99047, 92001, 80047,
   16015...10001). The tutorial pack UI runs with controls locked
   and auto-selects index 0 via GachaUI.GetCurrentLegendPackId
   (FirstOrDefault on IsLegendPackId), so the legendary starter
   needs to be the first legend pack in the list.

3. DbCardPoolProvider.GetPool falls back to all in-rotation cards
   when a LegendCardPack's base set has no rows. Pack 99047's
   base_pack_id is 90001, a synthetic "Throwback Rotation" category
   that doesn't correspond to a real card_set in the prod card
   master — its real pool is curated across older rotation sets
   (Altersphere through Colosseum). We don't have that membership
   map captured yet; the rotation fallback is broader than prod
   but produces a valid 8-card draw, which is what the tutorial
   needs to advance to step 100. TODO in code points at the
   real fix.

4. PackController.Open's tutorial path now consumes the granted
   ticket (decrement viewer.Items by packNumber for child.ItemId)
   and emits the post-state count in reward_list as
   {reward_type:4, reward_id:item_id, reward_num:post_count}.
   Without this, the pack stayed at item_number=1 forever, the
   shop kept showing it post-tutorial, and the next click hit
   /pack/open (not /tutorial/pack_open) which 501s on type_detail=5.

Also: docstring on PackConfigDto.SalesPeriodInfo flags the deferred
wire-fidelity fix (prod emits {"sales_period_time": "<complete_date>"}
for limited windows, [] for evergreens; we always emit {}) and the
retype from Dictionary<string,string?> to a typed
PackSalesPeriodInfoDto. Doesn't affect tutorial flow, deferred for
the pack-system rework.

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

SVSim.Database/Repositories/Pack/PackRepository.cs

@@ -13,6 +13,12 @@ public class PackRepository : IPackRepository
             .Include(p => p.ChildGachas)
             .Include(p => p.Banners)
             .Where(p => p.CommenceDate <= now && p.CompleteDate >= now)
+            // parent_gacha_id DESC matches the prod /pack/info wire order. The tutorial pack
+            // UI runs with controls locked and auto-selects the FIRST entry in
+            // pack_config_list, so the legendary starter pack (99047) MUST be index 0 for the
+            // tutorial to progress. Verified against data_dumps/traffic_prod_tutorial.ndjson —
+            // prod emits [99047, 92001, 80047, 16015..16011, 10032..10001].
+            .OrderByDescending(p => p.Id)
             .ToListAsync();
 
     public async Task<PackConfigEntry?> GetPack(int parentGachaId) =>