Door/hood sync via hinge spring instead of teleport (fixes NaN crash and parts falling off); join/leave toasts

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

MultiplayerManager.cs

@@ -65,6 +65,10 @@ namespace MSCO
         readonly TrafficSync traffic = new TrafficSync();
         readonly HingeSync hinges = new HingeSync();
         readonly ControlSync controls = new ControlSync();
+        readonly Toasts toasts = new Toasts();
+
+        void ToastJoined(string name) { toasts.Add(name, "joined the game", UiTheme.Online); }
+        void ToastLeft(string name) { toasts.Add(name, "left the game", UiTheme.Muted); }
         readonly Overlays overlays = new Overlays();
         bool isAdmin;                                          // Server hat uns als Admin gemeldet
         readonly HashSet<string> bannedNames = new HashSet<string>(); // P2P-Host: für diese Sitzung gebannt
@@ -928,6 +932,7 @@ namespace MSCO
             RemovePlayer(peerId);
             session.SendToAll(MsgType.PlayerLeft, NetSession.Build(w => w.Write(peerId)));
             SetStatus(p.Name + " left (" + reason + ")");
+            ToastLeft(p.Name);
         }
 
         string serverReason;   // Grund, den der Server/Host beim Trennen mitgeschickt hat
@@ -1144,6 +1149,7 @@ namespace MSCO
                 foreach (PlayerInfo p in list) { w.Write(p.Id); w.Write(p.Name); }
             }));
             session.SendToAll(MsgType.PlayerJoined, NetSession.Build(w => { w.Write(peerId); w.Write(name); }), peerId);
+            ToastJoined(name);
 
             if (MenuHelper.InGame)
             {
@@ -1216,6 +1222,7 @@ namespace MSCO
                     string name = r.ReadString();
                     AddPlayer(id, name, false);
                     SetStatus(name + " joined");
+                    ToastJoined(name);
                     break;
                 }
 
@@ -1223,7 +1230,7 @@ namespace MSCO
                 {
                     int id = r.ReadInt32();
                     PlayerInfo p;
-                    if (players.TryGetValue(id, out p)) SetStatus(p.Name + " left");
+                    if (players.TryGetValue(id, out p)) { SetStatus(p.Name + " left"); ToastLeft(p.Name); }
                     RemovePlayer(id);
                     break;
                 }
@@ -1960,7 +1967,7 @@ namespace MSCO
             if (MenuHelper.InMenu)
             {
                 lobby.Draw(this);
-                DrawPing();
+                DrawPing(); toasts.Draw();
                 overlays.Draw(this, false);
                 return;
             }
@@ -1977,7 +1984,7 @@ namespace MSCO
             }
 
             if (session != null) DrawHud();
-            DrawPing();
+            DrawPing(); toasts.Draw();
             overlays.Draw(this, session != null);
         }