Server closes connections gracefully so kick/ban/reset/shutdown messages arrive; status dot and HUD yellow until really connected (also while reconnecting)

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

Protocol.cs

@@ -89,6 +89,9 @@ public sealed class Connection
 
     readonly TcpClient client;
     readonly NetworkStream stream;
+    bool closing;            // Meldung gesendet, warten bis der Spieler sie gelesen hat (siehe CloseAfterSend)
+    DateTime closeDeadline;
+    string closingReason;
     readonly byte[] readBuffer = new byte[64 * 1024];
     byte[] buffer = new byte[64 * 1024];
     int count;
@@ -106,6 +109,11 @@ public sealed class Connection
     {
         var messages = new List<Message>();
         if (IsClosed) return messages;
+        if (closing)
+        {
+            DrainWhileClosing();
+            return messages;
+        }
         try
         {
             if (client.Client.Poll(0, SelectMode.SelectRead) && client.Available == 0)
@@ -131,7 +139,7 @@ public sealed class Connection
 
     public void Send(MsgType type, byte[] payload = null)
     {
-        if (IsClosed) return;
+        if (IsClosed || closing) return;
         try
         {
             byte[] frame = Wire.Frame(type, payload);
@@ -143,6 +151,38 @@ public sealed class Connection
         }
     }
 
+    /// <summary>
+    /// Sauber trennen, nachdem eine letzte Meldung gesendet wurde (Kick/Ban-Grund, Neu-Verbinden, Shutdown).
+    /// Sofortiges Close() mit noch ungelesenen Daten des Spielers (er schickt ständig Positionen) führt zu einem
+    /// TCP-Reset - dann geht die gerade gesendete Meldung verloren. Deshalb: nur die Sende-Richtung schließen,
+    /// eingehende Daten noch kurz lesen und verwerfen, dann erst schließen.
+    /// </summary>
+    public void CloseAfterSend(string reason)
+    {
+        if (IsClosed || closing) return;
+        closing = true;
+        closingReason = reason;
+        closeDeadline = DateTime.UtcNow.AddSeconds(3);
+        try { client.Client.Shutdown(SocketShutdown.Send); } catch { Close(reason); }
+    }
+
+    public bool IsClosing => closing && !IsClosed;
+
+    void DrainWhileClosing()
+    {
+        try
+        {
+            while (stream.DataAvailable)
+                if (stream.Read(readBuffer, 0, readBuffer.Length) <= 0) break;
+            bool remoteClosed = client.Client.Poll(0, SelectMode.SelectRead) && client.Available == 0;
+            if (remoteClosed || DateTime.UtcNow >= closeDeadline) Close(closingReason);
+        }
+        catch
+        {
+            Close(closingReason);
+        }
+    }
+
     public void Close(string reason)
     {
         if (IsClosed) return;