feat(battle-node): reveal copy tokens on play via baseIdx resolution

PlayActionsHandler + EchoHandler now call RecordCopyTokensFrom (ordered
after plain/choice mining) to resolve a copy add's baseIdx against the
side's live idx->cardId map and record copyIdx->cardId. A copy played in a
later (or same) frame synthesizes a knownList instead of degrading.

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

SVSim.BattleNode/Sessions/Dispatch/BattleSessionState.cs

@@ -67,4 +67,21 @@ internal sealed class BattleSessionState
         foreach (var (idx, cardId, isSelf) in KnownListBuilder.MineChoicePicks(orderList, keyAction))
             RecordToken(isSelf == 1 ? from : other, idx, cardId);
     }
+
+    /// <summary>Mine + record copy/clone-token identities (<see cref="KnownListBuilder.MineCopyTokens"/>)
+    /// into the correct side's map. A copy's source lives at <c>baseIdx</c> in the actor's own index
+    /// space, so the resolution side == the record side, both selected by the same <c>isSelf</c> routing
+    /// as <see cref="RecordTokensFrom"/>. Passing the LIVE per-side maps (via
+    /// <see cref="GetOrSeedDeckMap"/>, not snapshots) lets a copy that references a plain/choice token
+    /// added earlier THIS frame resolve — provided this runs AFTER
+    /// <see cref="RecordTokensFrom"/>/<see cref="RecordChoicePicksFrom"/> (the handler orders it last).
+    /// Seeding both maps up front matters because a copy-only frame (no concrete/choice add) would never
+    /// have hit <see cref="RecordToken"/> yet, leaving the maps unseeded.</summary>
+    public void RecordCopyTokensFrom(IBattleParticipant from, IBattleParticipant other, object? orderList)
+    {
+        var selfMap = GetOrSeedDeckMap(from);
+        var otherMap = GetOrSeedDeckMap(other);
+        foreach (var (idx, cardId, isSelf) in KnownListBuilder.MineCopyTokens(orderList, selfMap, otherMap))
+            RecordToken(isSelf == 1 ? from : other, idx, cardId);
+    }
 }