feat(battle-node): cross-side gift + Echo-frame token mining

Close the two generated-token gaps that desynced PvP live test #3 (the
Forestcraft Fairy), both sourced from the 2026-06-03 decomp-validation table.

- MineAddOps now returns (idx, cardId, isSelf) and no longer drops isSelf:0.
  isSelf is the sender's perspective tag on CardObj.IsPlayer (RegisterToken.cs:22)
  and a card has one CardObj.Index, so an isSelf:0 add is the opponent's card.
- New shared BattleSessionState.RecordTokensFrom routes isSelf:1 -> sender,
  isSelf:0 -> opponent (the gift lives in the recipient's map, consulted when
  they play it). PlayActionsHandler delegates to it.
- EchoHandler now mines via the same helper but still returns no routes. An
  Echo's orderList carries the same add-op shape as a send (MakeEchoData ->
  MakeCommonSendAndEchoCardData), so MineAddOps applies verbatim; mining != relaying.

Choice/copy/private-group adds stay skipped (no concrete cardId). Full solution
963/963 green.

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

SVSim.UnitTests/BattleNode/Integration/CaptureConformanceTests.cs

@@ -322,7 +322,7 @@ public class CaptureConformanceTests
                   ["card"] = new Dictionary<string, object?> { ["cardId"] = 900811111L } } },
         };
         var map = new Dictionary<int, long>();
-        foreach (var (idx, cardId) in SVSim.BattleNode.Sessions.Dispatch.KnownListBuilder.MineAddOps(generatingOrderList))
+        foreach (var (idx, cardId, _) in SVSim.BattleNode.Sessions.Dispatch.KnownListBuilder.MineAddOps(generatingOrderList))
             map[idx] = cardId;
 
         var playOrderList = new List<object?>