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.BattleNode/Sessions/Dispatch/Handlers/InitBattleHandler.cs

@@ -12,7 +12,7 @@ internal sealed class InitBattleHandler : IFrameHandler
         {
             var r = new List<DispatchRoute>
             {
-                new(ctx.From, BattleFrames.BuildAck(NetworkBattleUri.InitBattle), true),
+                new(ctx.From, BattleFrames.BuildAck(NetworkBattleUri.InitBattle), Stock.Bypass),
             };
             ctx.SenderPhase = BattleSessionPhase.AwaitingLoaded;
             return r;
@@ -26,7 +26,7 @@ internal sealed class InitBattleHandler : IFrameHandler
                 new(ctx.From, ServerBattleFrames.BuildMatched(
                     ctx.From.Context, ctx.Other.Context, ctx.From.ViewerId, ctx.Other.ViewerId,
                     ctx.BattleId, BattleSeeds.Stable(ctx.State.MasterSeed),
-                    ctx.State.GetShuffledDeck(ctx.From)), false),
+                    ctx.State.GetShuffledDeck(ctx.From)), Stock.Normal),
             };
             ctx.SenderPhase = BattleSessionPhase.AwaitingLoaded;
             return r;