D1-3 (XC-8): route PayloadHandler Send-Tell through shared BuildTellCommand (IsPublic at call-site)

HellionChat/PayloadHandler.cs

@@ -263,13 +263,15 @@ internal sealed class PayloadHandler
             // Eureka, Bozja and Occult need special handling as tells work different
             if (!Sheets.IsInForay())
             {
-                // §6.9: single SetPendingMessage call; v1.5.6 used incremental Chat += writes
-                var builder = $"/tell {player.PlayerName}";
-                if (world.Value.IsPublic)
-                    builder += $"@{world.Value.Name}";
-
-                builder += " ";
-                _inputBar.SetPendingMessage(builder);
+                // §6.9: single SetPendingMessage call; v1.5.6 used incremental Chat += writes.
+                // XC-8: shares the /tell builder with the native detours. IsPublic (not
+                // IsNullOrEmpty) is resolved HERE — a private/null world must NOT leak @World.
+                _inputBar.SetPendingMessage(
+                    GameFunctions.Chat.BuildTellCommand(
+                        player.PlayerName,
+                        world.Value.IsPublic ? world.Value.Name.ToString() : null
+                    )
+                );
             }
             else if (validContentId)
             {