feat(import): import owned card collection with unknown-card skip

Extends POST /admin/import_viewer to accept owned_cards (snapshot full-replace).
Unknown card_ids are skipped, counted in skipped_card_count on the response, and
logged server-side. Count is clamped to OwnedCardEntry.MaxCopies (3). Also injects
ILogger into AdminController and adds Cards/Items/Decks to the viewer reload graph.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

SVSim.UnitTests/Controllers/AdminControllerTests.cs

@@ -115,4 +115,84 @@ public class AdminControllerTests
 
         Assert.That(response.StatusCode, Is.EqualTo(HttpStatusCode.BadRequest));
     }
+
+    [Test]
+    public async Task ImportViewer_imports_owned_cards_and_skips_unknown()
+    {
+        using var factory = new SVSimTestFactory();
+        using var client = factory.CreateClient();
+
+        // 10001001 is in the minimal test card set; 99999999 is not.
+        var response = await client.PostAsJsonAsync("/admin/import_viewer", new ImportViewerRequest
+        {
+            SteamId = 76_561_198_111_222_333UL,
+            OwnedCards = new List<ImportCard>
+            {
+                new() { CardId = 10001001L, Count = 2, IsProtected = true },
+                new() { CardId = 99999999L, Count = 1, IsProtected = false },
+            }
+        });
+
+        Assert.That(response.StatusCode, Is.EqualTo(HttpStatusCode.OK),
+            await response.Content.ReadAsStringAsync());
+        var body = await response.Content.ReadFromJsonAsync<ImportViewerResponse>(JsonOptions);
+        Assert.That(body!.SkippedCardCount, Is.EqualTo(1), "Unknown 99999999 must be skipped and counted.");
+
+        using var scope = factory.Services.CreateScope();
+        var db = scope.ServiceProvider.GetRequiredService<SVSimDbContext>();
+        var stored = await db.Viewers.Include(v => v.Cards).ThenInclude(c => c.Card)
+            .FirstAsync(v => v.Id == body.ViewerId);
+
+        Assert.That(stored.Cards.Count, Is.EqualTo(1), "Only the known card should be stored.");
+        var owned = stored.Cards.Single();
+        Assert.That(owned.Card.Id, Is.EqualTo(10001001L));
+        Assert.That(owned.Count, Is.EqualTo(2));
+        Assert.That(owned.IsProtected, Is.True);
+    }
+
+    [Test]
+    public async Task ImportViewer_clamps_card_count_to_max_copies()
+    {
+        using var factory = new SVSimTestFactory();
+        using var client = factory.CreateClient();
+
+        var response = await client.PostAsJsonAsync("/admin/import_viewer", new ImportViewerRequest
+        {
+            SteamId = 76_561_198_111_222_334UL,
+            OwnedCards = new List<ImportCard> { new() { CardId = 10001002L, Count = 5 } }
+        });
+        var body = await response.Content.ReadFromJsonAsync<ImportViewerResponse>(JsonOptions);
+
+        using var scope = factory.Services.CreateScope();
+        var db = scope.ServiceProvider.GetRequiredService<SVSimDbContext>();
+        var stored = await db.Viewers.Include(v => v.Cards).ThenInclude(c => c.Card)
+            .FirstAsync(v => v.Id == body!.ViewerId);
+        Assert.That(stored.Cards.Single().Count, Is.EqualTo(3),
+            "Count must clamp to OwnedCardEntry.MaxCopies (3).");
+    }
+
+    [Test]
+    public async Task ImportViewer_replaces_existing_card_collection()
+    {
+        using var factory = new SVSimTestFactory();
+        const ulong steamId = 76_561_198_111_222_335UL;
+        long viewerId = await factory.SeedViewerAsync(steamId: steamId);
+        await factory.SeedOwnedCardAsync(viewerId, 10001001L, count: 3);
+
+        using var client = factory.CreateClient();
+        var response = await client.PostAsJsonAsync("/admin/import_viewer", new ImportViewerRequest
+        {
+            SteamId = steamId,
+            OwnedCards = new List<ImportCard> { new() { CardId = 10001002L, Count = 1 } }
+        });
+        Assert.That(response.StatusCode, Is.EqualTo(HttpStatusCode.OK),
+            await response.Content.ReadAsStringAsync());
+
+        using var scope = factory.Services.CreateScope();
+        var db = scope.ServiceProvider.GetRequiredService<SVSimDbContext>();
+        var stored = await db.Viewers.Include(v => v.Cards).ThenInclude(c => c.Card)
+            .FirstAsync(v => v.Id == viewerId);
+        Assert.That(stored.Cards.Select(c => c.Card.Id), Is.EquivalentTo(new[] { 10001002L }),
+            "Full replace: the pre-seeded 10001001 must be gone, only 10001002 present.");
+    }
 }