feat(sleeve): shop catalog + /sleeve/{info,buy} endpoints

Schema: SleeveShopSeries -> SleeveShopProducts -> Rewards (owned).
Migration AddSleeveShop creates 3 tables with FK cascade.

Importer mirrors BuildDeck pattern: find-or-create per series/product,
rewards replaced wholesale on rerun (owned collection). 10 series,
270 products imported from seeds/sleeve-shop.json.

Controller:
- /sleeve/info returns wire-faithful dict-keyed shape
  ({sleeve_list: {<series_id>: {product_info: {<product_id>: ...}}}}).
  is_purchased_product derived from viewer.Sleeves.Contains(sleeve_id).
- /sleeve/buy: sales_type 0=free / 1=crystal / 2=rupy / 3=ticket(501).
  Validates series_product mismatch, currency, already-purchased.
  Currency debited with post-state-total reward_list entry; cosmetic
  grants dispatched through RewardGrantService.ApplyAsync (covers
  sleeve + emblem bundled grants per product).

476 tests pass (was 466; +10 sleeve tests).

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

SVSim.Database/Models/SleeveShopSeriesEntry.cs

@@ -0,0 +1,16 @@
+using SVSim.Database.Common;
+
+namespace SVSim.Database.Models;
+
+/// <summary>
+/// One sleeve-shop series (a themed collection — e.g. series 3019 "BattlePass sleeves",
+/// series 3004 "Granblue Fantasy collab"). PK = wire series_id. IsEnabled gates whether
+/// /sleeve/info renders this series.
+/// </summary>
+public class SleeveShopSeriesEntry : BaseEntity<int>
+{
+    public bool IsNew { get; set; }
+    public bool IsEnabled { get; set; }
+
+    public List<SleeveShopProductEntry> Products { get; set; } = new();
+}