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/Protocol/Bodies/PlayActionsBroadcastBody.cs

@@ -24,7 +24,8 @@ public sealed record PlayActionsBroadcastBody(
 /// until the chosen card is played — and passed through for a visible (open:1) board choice (§6,
 /// provisional pending live confirmation).</summary>
 public sealed record KeyActionEntry(
-    [property: JsonPropertyName("type")] int Type,
+    [property: JsonPropertyName("type")]
+    [property: JsonConverter(typeof(JsonNumberEnumConverter<KeyActionType>))] KeyActionType Type,
     [property: JsonPropertyName("cardId")] long CardId,
     [property: JsonPropertyName("selectCard")] SelectCardEntry? SelectCard);