refactor(battle-node): address final-review minor notes (comments + test backfill)

- PlayActionsHandler doc: drop the phantom 'with a debug log' (handlers are
  stateless singletons with no logger); say token plays degrade silently.
- KnownListBuilder.ExtractMoveTo doc: note first-match-wins semantics and the
  send-side==recv-side 'to' assumption pending recv-capture confirmation.
- KnownListBuilderTests: add multi-move first-match coverage and the
  in-deck-but-no-matching-move null branch for BuildPlayedCard.

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

SVSim.BattleNode/Sessions/Dispatch/Handlers/PlayActionsHandler.cs

@@ -5,8 +5,8 @@ namespace SVSim.BattleNode.Sessions.Dispatch.Handlers;
 
 /// <summary>PvP PlayActions translator (vanilla deck-card slice). Synthesizes the opponent-facing
 /// knownList from the sender's idx->cardId map + the orderList move op, renames targetList ->
-/// oppoTargetList, drops orderList, consumes keyAction. Token plays (idx>deck) degrade to
-/// {playIdx,type} with a debug log. Scripted/Bot drop (no rule).</summary>
+/// oppoTargetList, drops orderList, consumes keyAction. Token plays (idx>deck) degrade silently to
+/// {playIdx,type} (no knownList). Scripted/Bot drop (no rule).</summary>
 internal sealed class PlayActionsHandler : IFrameHandler
 {
     public IReadOnlyList<DispatchRoute> Handle(FrameDispatchContext ctx)