feat(battle-node): NetworkBattleUri / EmitCategory enums and MsgEnvelope record

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

SVSim.BattleNode/Protocol/ReceiveNodeResultCode.cs

@@ -0,0 +1,16 @@
+namespace SVSim.BattleNode.Protocol;
+
+/// <summary>The "resultCode" field on synchronize pushes. 1=Success, else error.</summary>
+public enum ReceiveNodeResultCode
+{
+    None = 0,
+    Success = 1,
+    Different_UUID = 30001,
+    RedisReplyError = 30002,
+    UnexistUserinfoError = 30003,
+    MatchingTimeOut = 30201,
+    UnmatchedError = 30211,
+    CurrentBattleError = 30212,
+    UnexpectedPhaseError = 30213,
+    // Other codes from spec/enums.md added as needed; v1 only triggers the four above.
+}