Improve WebSocket receive to handle multi-frame messages

The receive logic now accumulates all frames until EndOfMessage, ensuring complete messages are read even if fragmented. This change improves reliability when handling large or fragmented WebSocket messages.

WelsonJS.Toolkit/WelsonJS.Launcher/WebSocketManager.cs

@@ -119,7 +119,7 @@ namespace WelsonJS.Launcher
             throw new InvalidOperationException("Unreachable");
         }
 
-        // Actual send and receive implementation
+        // Actual send and receive implementation that accumulates all frames until EndOfMessage
         private async Task<string> TrySendAndReceiveAsync(string host, int port, string path, byte[] buf, CancellationToken token)
         {
             try
@@ -129,12 +129,41 @@ namespace WelsonJS.Launcher
                 if (sock.State != WebSocketState.Open)
                     throw new WebSocketException("WebSocket is not in an open state");
 
+                // Send the message as a single text frame
                 await sock.SendAsync(new ArraySegment<byte>(buf), WebSocketMessageType.Text, true, token);
 
-                byte[] recv = new byte[4096];
-                var result = await sock.ReceiveAsync(new ArraySegment<byte>(recv), token);
+                // Receive loop: keep reading until the logical message ends (EndOfMessage == true)
+                byte[] buffer = new byte[8192];
+                using (var ms = new System.IO.MemoryStream())
+                {
+                    while (true)
+                    {
+                        var result = await sock.ReceiveAsync(new ArraySegment<byte>(buffer), token);
 
-                return Encoding.UTF8.GetString(recv, 0, result.Count);
+                        if (result.MessageType == WebSocketMessageType.Close)
+                        {
+                            // Server requested closure; acknowledge and throw
+                            try { await sock.CloseAsync(WebSocketCloseStatus.NormalClosure, "Closing as requested by server", token); }
+                            catch { /* ignore close exceptions */ }
+
+                            throw new WebSocketException($"WebSocket closed by server: {sock.CloseStatus} {sock.CloseStatusDescription}");
+                        }
+
+                        if (result.Count > 0)
+                        {
+                            ms.Write(buffer, 0, result.Count);
+                        }
+
+                        if (result.EndOfMessage)
+                        {
+                            // Entire message received
+                            break;
+                        }
+                    }
+
+                    // Decode UTF-8 text message
+                    return Encoding.UTF8.GetString(ms.ToArray());
+                }
             }
             catch (WebSocketException ex)
             {
@@ -146,4 +175,4 @@ namespace WelsonJS.Launcher
             }
         }
     }
-}
+}