test(battle-node): end-to-end drafted deck flows into Matched frame

Seeds a viewer + completed TK2 run, drives the WS handshake to Matched, and
asserts every cardId in selfDeck matches the run's SelectedCardIdsJson. Read
from RawBody (codec's wire-form deserialization) — not from MatchedBody —
since the test client gets the JSON-roundtripped envelope.

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

SVSim.UnitTests/BattleNode/Integration/BattleNodeFlowTests.cs

@@ -1,9 +1,12 @@
+using System.Text.Json;
 using Microsoft.AspNetCore.Mvc.Testing;
 using Microsoft.Extensions.DependencyInjection;
 using NUnit.Framework;
 using SVSim.BattleNode.Bridge;
 using SVSim.BattleNode.Protocol;
 using SVSim.BattleNode.Wire;
+using SVSim.Database;
+using SVSim.Database.Models;
 using SVSim.EmulatedEntrypoint;
 using SVSim.UnitTests.Infrastructure;
 
@@ -73,4 +76,86 @@ public class BattleNodeFlowTests
         CountryCode: "KOR", UserName: "Player", SleeveId: "3000011",
         EmblemId: "701441011", DegreeId: "300003", FieldId: 43, IsOfficial: 0,
         BattleType: 11);
+
+    /// <summary>
+    /// End-to-end: a viewer with a real TK2 run sees their drafted card-ids in the Matched
+    /// frame's selfDeck. This is the "visible win" — proves the full plumbing chain works
+    /// against an actual seeded viewer.
+    /// </summary>
+    [Test]
+    [Timeout(30000)]
+    public async Task Matched_frame_contains_drafted_deck_cards()
+    {
+        await using var factory = new SVSimTestFactory();
+        var vid = await factory.SeedViewerAsync();
+        var draftedDeck = Enumerable.Range(1, 30).Select(i => 200_000_000L + i).ToList();
+
+        using (var seedScope = factory.Services.CreateScope())
+        {
+            var db = seedScope.ServiceProvider.GetRequiredService<SVSimDbContext>();
+            db.ViewerArenaTwoPickRuns.Add(new ViewerArenaTwoPickRun
+            {
+                ViewerId = vid,
+                EntryId = 1,
+                ClassId = 1,
+                LeaderSkinId = 1,
+                SelectedCardIdsJson = JsonSerializer.Serialize(draftedDeck),
+                IsSelectCompleted = true,
+                MaxBattleCount = 5,
+                CandidateClassIdsJson = "[1,2,3]",
+                PendingPickSetsJson = "[]",
+                ResultListJson = "[]",
+                NextCandidateId = 1,
+            });
+            await db.SaveChangesAsync();
+        }
+
+        using var scope = factory.Services.CreateScope();
+        var builder = scope.ServiceProvider.GetRequiredService<SVSim.EmulatedEntrypoint.Services.IMatchContextBuilder>();
+        var ctx = await builder.BuildForTwoPickAsync(vid);
+        var bridge = factory.Services.GetRequiredService<IMatchingBridge>();
+
+        using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(15));
+        var ct = cts.Token;
+        var pending = bridge.RegisterPendingBattle(viewerId: vid, context: ctx);
+
+        var key = MakeKey();
+        var encryptedVid = NodeCrypto.EncryptForNode(vid.ToString(), key);
+        var wsUri = new Uri($"ws://localhost/socket.io/?BattleId={pending.BattleId}&viewerId={Uri.EscapeDataString(encryptedVid)}&EIO=3&transport=websocket");
+
+        var wsClient = factory.Server.CreateWebSocketClient();
+        var ws = await wsClient.ConnectAsync(wsUri, ct);
+        await using var client = new RawSocketIoTestClient(ws);
+        await client.ConsumeHandshakeAsync(ct);
+
+        // InitNetwork → ack
+        await client.SendMsgAsync(MakeEnvelopeWith(vid, NetworkBattleUri.InitNetwork, pubSeq: 1), key, ct);
+        await client.ReceiveSynchronizeAsync(ct);
+
+        // InitBattle → Matched (this is the frame we care about)
+        await client.SendMsgAsync(MakeEnvelopeWith(vid, NetworkBattleUri.InitBattle, pubSeq: 2), key, ct);
+        var matched = await client.ReceiveSynchronizeAsync(ct);
+        Assert.That(matched.Uri, Is.EqualTo(NetworkBattleUri.Matched));
+
+        // MsgEnvelope.FromJson always inflates Body as a RawBody dictionary — selfDeck is a
+        // List<object?> of nested dicts with int "idx" + long "cardId" keys.
+        var body = ((RawBody)matched.Body).Entries;
+        var selfDeck = (List<object?>)body["selfDeck"]!;
+        Assert.That(selfDeck.Count, Is.EqualTo(30));
+        for (int i = 0; i < 30; i++)
+        {
+            var entry = (Dictionary<string, object?>)selfDeck[i]!;
+            Assert.That((long)entry["idx"]!, Is.EqualTo(i + 1L),
+                $"slot {i}: idx should be 1-based position");
+            Assert.That((long)entry["cardId"]!, Is.EqualTo(draftedDeck[i]),
+                $"slot {i}: cardId should match the drafted card");
+        }
+    }
+
+    private static MsgEnvelope MakeEnvelopeWith(long vid, NetworkBattleUri uri, long pubSeq) =>
+        new(uri, ViewerId: vid, Uuid: "udid-test", Bid: null, Try: 0,
+            Cat: uri == NetworkBattleUri.InitNetwork ? EmitCategory.General
+                 : uri == NetworkBattleUri.InitBattle ? EmitCategory.Matching
+                 : EmitCategory.Battle,
+            PubSeq: pubSeq, PlaySeq: null, Body: new RawBody(new Dictionary<string, object?>()));
 }