Server new game: start a fresh world when the server says so

StartGame carries a second flag (new game); the client then starts MSC's new
game instead of loading the (empty) received save.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

MultiplayerManager.cs

@@ -1596,6 +1596,15 @@ namespace MSCO
                     receivingSave = false;
                     // Später beigetreten: nach dem Laden neben den Host setzen
                     teleportToHost = r.BaseStream.Length > 0 && r.ReadBoolean();
+                    // Server mit "neues Spiel" (Panel): kein Spielstand - hier ein neues Spiel starten (Server ab 2.9.3)
+                    bool serverNewGame = r.BaseStream.Length - r.BaseStream.Position >= 1 && r.ReadBoolean();
+                    if (serverNewGame)
+                    {
+                        SetStatus("The server starts a new game - creating a fresh world...");
+                        MscoLog.Info("[MSCO] Server has a new game - starting a fresh world");
+                        MenuHelper.StartNewGame();
+                        break;
+                    }
                     SetStatus(dedicated ? "Loading server world..." : "Loading host's game...");
                     MenuHelper.StartGame();
                     break;