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.EmulatedEntrypoint/Models/Dtos/Responses/Sleeve/SleeveBuyResponse.cs

@@ -0,0 +1,19 @@
+using System.Text.Json.Serialization;
+using MessagePack;
+using SVSim.EmulatedEntrypoint.Models.Dtos;
+
+namespace SVSim.EmulatedEntrypoint.Models.Dtos.Responses.Sleeve;
+
+/// <summary>
+/// /sleeve/buy response. <c>reward_list</c> items use reward_id/reward_num
+/// (POST-STATE-TOTAL for currencies, grant id+count for cosmetics) — driven by
+/// <c>PlayerStaticData.UpdateHaveUserGoodsNumByJsonData</c>. Mirrors the /pack/open +
+/// /build_deck/buy reward_list semantics.
+/// </summary>
+[MessagePackObject]
+public class SleeveBuyResponse
+{
+    [JsonPropertyName("reward_list")]
+    [Key("reward_list")]
+    public List<RewardListEntry> RewardList { get; set; } = new();
+}