refactor(battlenode): close §A boolean-blindness items (MinedToken, Stock, KeyActionType)

Behavior-preserving; 231 BattleNode tests green.

- MinedToken record struct replaces the transpose-prone (int Idx, long CardId,
  CardOwner IsSelf) tuple returned by KnownListBuilder.Mine*. Positional deconstruct
  keeps the Record*From call sites unchanged.
- enum Stock { Normal, Bypass } replaces the negative `bool noStock` on
  IBattleParticipant.PushAsync and DispatchRoute, threaded through both participants,
  BattleSession, and all handler construction sites.
- enum KeyActionType mirrors the client's SendKeyActionDataManager.KeyActionType;
  the StripKeyActionForOpponent guard compares named values, KeyActionEntry.Type is
  the enum (wire-identical via JsonNumberEnumConverter).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

SVSim.UnitTests/BattleNode/Sessions/BattleSessionStateTests.cs

@@ -14,7 +14,7 @@ public class BattleSessionStateTests
         public MatchContext Context { get; }
         public event Func<SVSim.BattleNode.Protocol.MsgEnvelope, CancellationToken, Task>? FrameEmitted;
         public StubParticipant(long id, MatchContext ctx) { ViewerId = id; Context = ctx; }
-        public Task PushAsync(SVSim.BattleNode.Protocol.MsgEnvelope e, bool n, CancellationToken c) => Task.CompletedTask;
+        public Task PushAsync(SVSim.BattleNode.Protocol.MsgEnvelope e, Stock n, CancellationToken c) => Task.CompletedTask;
         public Task RunAsync(CancellationToken c) => Task.CompletedTask;
         public Task TerminateAsync(BattleFinishReason r) => Task.CompletedTask;
         public ValueTask DisposeAsync() => ValueTask.CompletedTask;