feat(inventory): read-side methods on IInventoryService + tx

EffectiveBalance/OwnsCard/OwnsCosmetic on the tx are freeplay-aware
against the live viewer. EffectiveOwnedCardsAsync/EffectiveCosmeticsAsync
on the service mirror today's ViewerEntitlements projections (used by
/load/index).

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

SVSim.UnitTests/Services/Inventory/InventoryReadSideTests.cs

@@ -0,0 +1,128 @@
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.DependencyInjection;
+using SVSim.Database;
+using SVSim.Database.Enums;
+using SVSim.Database.Models;
+using SVSim.Database.Services;
+using SVSim.Database.Services.Inventory;
+using SVSim.UnitTests.Infrastructure;
+
+namespace SVSim.UnitTests.Services.Inventory;
+
+public class InventoryReadSideTests
+{
+    [Test]
+    public async Task EffectiveBalance_returns_viewer_currency_when_not_freeplay()
+    {
+        using var factory = new SVSimTestFactory();
+        long viewerId = await factory.SeedViewerAsync();
+        using var scope = factory.Services.CreateScope();
+        var ctx = scope.ServiceProvider.GetRequiredService<SVSimDbContext>();
+        var v = await ctx.Viewers.FirstAsync(x => x.Id == viewerId);
+        v.Currency.Crystals = 1234;
+        await ctx.SaveChangesAsync();
+
+        // Re-load viewer with inventory graph for the read-side call
+        var v2 = await ctx.Viewers.AsNoTracking().FirstAsync(x => x.Id == viewerId);
+        var inv = scope.ServiceProvider.GetRequiredService<IInventoryService>();
+        Assert.That(inv.EffectiveBalance(v2, SpendCurrency.Crystal), Is.EqualTo(1234));
+    }
+
+    [Test]
+    public async Task EffectiveOwnedCardsAsync_returns_non_null_collection()
+    {
+        using var factory = new SVSimTestFactory();
+        long viewerId = await factory.SeedViewerAsync();
+        using var scope = factory.Services.CreateScope();
+        var ctx = scope.ServiceProvider.GetRequiredService<SVSimDbContext>();
+        var v = await ctx.Viewers
+            .Include(x => x.Cards).ThenInclude(c => c.Card)
+            .FirstAsync(x => x.Id == viewerId);
+
+        var inv = scope.ServiceProvider.GetRequiredService<IInventoryService>();
+        var owned = await inv.EffectiveOwnedCardsAsync(v);
+
+        Assert.That(owned, Is.Not.Null);
+        // If there are basic cards seeded (IsBasic=true) they should be protected;
+        // if none are seeded the collection may be empty — just confirm it doesn't throw.
+    }
+
+    [Test]
+    public async Task EffectiveBalance_returns_freeplay_amount_when_freeplay_enabled()
+    {
+        using var factory = new SVSimTestFactory(freeplayEnabled: true);
+        long viewerId = await factory.SeedViewerAsync();
+        using var scope = factory.Services.CreateScope();
+        var ctx = scope.ServiceProvider.GetRequiredService<SVSimDbContext>();
+        var v = await ctx.Viewers.AsNoTracking().FirstAsync(x => x.Id == viewerId);
+
+        var inv = scope.ServiceProvider.GetRequiredService<IInventoryService>();
+        var freeCfg = scope.ServiceProvider.GetRequiredService<IGameConfigService>().Get<SVSim.Database.Models.Config.FreeplayConfig>();
+        Assert.That(inv.EffectiveBalance(v, SpendCurrency.Crystal), Is.EqualTo(checked((long)freeCfg.CurrencyAmount)));
+    }
+
+    [Test]
+    public async Task Transaction_EffectiveBalance_matches_viewer_balance()
+    {
+        using var factory = new SVSimTestFactory();
+        long viewerId = await factory.SeedViewerAsync();
+        using var scope = factory.Services.CreateScope();
+        var ctx = scope.ServiceProvider.GetRequiredService<SVSimDbContext>();
+        var v = await ctx.Viewers.FirstAsync(x => x.Id == viewerId);
+        v.Currency.Crystals = 5678;
+        await ctx.SaveChangesAsync();
+
+        var inv = scope.ServiceProvider.GetRequiredService<IInventoryService>();
+        await using var tx = await inv.BeginAsync(viewerId);
+
+        Assert.That(tx.EffectiveBalance(SpendCurrency.Crystal), Is.EqualTo(5678));
+    }
+
+    [Test]
+    public async Task Transaction_OwnsCard_returns_true_when_card_owned()
+    {
+        using var factory = new SVSimTestFactory();
+        long viewerId = await factory.SeedViewerAsync();
+        long cardId = await factory.SeedCardAsync();
+        await factory.SeedOwnedCardAsync(viewerId, cardId, 1);
+        using var scope = factory.Services.CreateScope();
+        var inv = scope.ServiceProvider.GetRequiredService<IInventoryService>();
+        await using var tx = await inv.BeginAsync(viewerId);
+
+        Assert.That(tx.OwnsCard(cardId), Is.True);
+    }
+
+    [Test]
+    public async Task Transaction_OwnsCard_returns_false_when_card_not_owned()
+    {
+        using var factory = new SVSimTestFactory();
+        long viewerId = await factory.SeedViewerAsync();
+        long cardId = await factory.SeedCardAsync();
+        // Do NOT seed owned card
+        using var scope = factory.Services.CreateScope();
+        var inv = scope.ServiceProvider.GetRequiredService<IInventoryService>();
+        await using var tx = await inv.BeginAsync(viewerId);
+
+        Assert.That(tx.OwnsCard(cardId), Is.False);
+    }
+
+    [Test]
+    public async Task Transaction_OwnsCosmetic_returns_true_when_owned()
+    {
+        using var factory = new SVSimTestFactory();
+        long viewerId = await factory.SeedViewerAsync();
+        using var scope = factory.Services.CreateScope();
+        var ctx = scope.ServiceProvider.GetRequiredService<SVSimDbContext>();
+        const int sleeveId = 2_000_040_000;
+        var sleeve = new SleeveEntry { Id = sleeveId };
+        ctx.Sleeves.Add(sleeve);
+        var v = await ctx.Viewers.Include(x => x.Sleeves).FirstAsync(x => x.Id == viewerId);
+        v.Sleeves.Add(sleeve);
+        await ctx.SaveChangesAsync();
+
+        var inv = scope.ServiceProvider.GetRequiredService<IInventoryService>();
+        await using var tx = await inv.BeginAsync(viewerId);
+
+        Assert.That(tx.OwnsCosmetic(CosmeticType.Sleeve, sleeveId), Is.True);
+    }
+}