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/SVSimDbContext.cs

@@ -70,6 +70,8 @@ public class SVSimDbContext : DbContext
     public DbSet<PackConfigEntry> Packs => Set<PackConfigEntry>();
     public DbSet<BuildDeckSeriesEntry> BuildDeckSeries => Set<BuildDeckSeriesEntry>();
     public DbSet<BuildDeckProductEntry> BuildDeckProducts => Set<BuildDeckProductEntry>();
+    public DbSet<SleeveShopSeriesEntry> SleeveShopSeries => Set<SleeveShopSeriesEntry>();
+    public DbSet<SleeveShopProductEntry> SleeveShopProducts => Set<SleeveShopProductEntry>();
     public DbSet<MaintenanceCardEntry> MaintenanceCards => Set<MaintenanceCardEntry>();
     public DbSet<FeatureMaintenanceEntry> FeatureMaintenances => Set<FeatureMaintenanceEntry>();
     public DbSet<PreReleaseInfo> PreReleaseInfos => Set<PreReleaseInfo>();
@@ -180,6 +182,14 @@ public class SVSimDbContext : DbContext
 
         modelBuilder.Entity<BuildDeckProductEntry>().HasIndex(p => p.SeriesId);
 
+        modelBuilder.Entity<SleeveShopProductEntry>().OwnsMany(p => p.Rewards);
+        modelBuilder.Entity<SleeveShopProductEntry>()
+            .HasOne(p => p.Series)
+            .WithMany(s => s.Products)
+            .HasForeignKey(p => p.SeriesId)
+            .OnDelete(DeleteBehavior.Cascade);
+        modelBuilder.Entity<SleeveShopProductEntry>().HasIndex(p => p.SeriesId);
+
         modelBuilder.Entity<CardCosmeticReward>(b =>
         {
             b.HasKey(r => new { r.CardId, r.Type, r.CosmeticId });