diag(game-server): log stateless handshake packet size vs expected

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/Prospect.Unreal/Net/StatelessConnectHandlerComponent.cs

@@ -185,6 +185,8 @@ public class StatelessConnectHandlerComponent : HandlerComponent
 
     public override void Incoming(FBitReader packet)
     {
+        var diagTotalBits = packet.GetBitsLeft();
+
         if (_magicHeader.Length > 0)
         {
             // Skip magic header.
@@ -192,6 +194,11 @@ public class StatelessConnectHandlerComponent : HandlerComponent
         }
 
         var bHandshakePacket = packet.ReadBit() && !packet.IsError();
+
+        // [HS-DIAG] Compare the incoming packet against what the stateless handshake expects.
+        // The Cycle client may use a magic header / different handshake size than 227 bits.
+        Logger.Information("[HS-DIAG] Incoming totalBits={Total} magicLen={Magic} bHandshake={HS} bitsLeftAfterFlag={Left} expectAfterFlag={Exp}",
+            diagTotalBits, _magicHeader.Length, bHandshakePacket, packet.GetBitsLeft(), HandshakePacketSizeBits - 1);
         if (bHandshakePacket)
         {
             var bRestartHandshake = false;