Fix pipe ACL: switch from named pipe to TCP loopback

Named pipe created by SYSTEM service denied connection from user process.
TCP loopback socket (127.0.0.1:random) has no cross-session ACL issues.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

agent-cs/CaptureModeRunner.cs

@@ -1,24 +1,25 @@
 using System.Drawing;
 using System.Drawing.Imaging;
-using System.IO.Pipes;
+using System.Net.Sockets;
 
 namespace ITNexusAgent;
 
 // Läuft als User-Prozess (via schtasks), nicht als SYSTEM-Service
-// Captured den Desktop und schickt JPEG-Frames via Named Pipe an den Service
+// Captured den Desktop und schickt JPEG-Frames via TCP Loopback an den Service
 public static class CaptureModeRunner
 {
     private static readonly ImageCodecInfo JpegCodec =
         ImageCodecInfo.GetImageEncoders().First(c => c.FormatID == ImageFormat.Jpeg.Guid);
 
-    public static void Run(string pipeName)
+    public static void Run(string portStr)
     {
-        if (string.IsNullOrEmpty(pipeName)) return;
+        if (!int.TryParse(portStr, out var port) || port <= 0) return;
 
         try
         {
-            using var pipe = new NamedPipeClientStream(".", pipeName, PipeDirection.Out);
-            pipe.Connect(5000); // 5s timeout
+            using var tcp = new TcpClient();
+            tcp.Connect("127.0.0.1", port);
+            var stream = tcp.GetStream();
 
             var encParams = new EncoderParameters(1);
             encParams.Param[0] = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, 60L);
@@ -32,7 +33,7 @@ public static class CaptureModeRunner
             int totalW = right - left;
             int totalH = bottom - top;
 
-            while (pipe.IsConnected)
+            while (tcp.Connected)
             {
                 try
                 {
@@ -47,16 +48,16 @@ public static class CaptureModeRunner
                         jpeg = ms.ToArray();
                     }
 
-                    // Länge (4 Bytes LE) + JPEG-Daten
-                    pipe.Write(BitConverter.GetBytes(jpeg.Length));
-                    pipe.Write(jpeg);
-                    pipe.Flush();
+                    // 4-Byte Länge (LE) + JPEG-Daten
+                    stream.Write(BitConverter.GetBytes(jpeg.Length));
+                    stream.Write(jpeg);
+                    stream.Flush();
                 }
                 catch { break; }
 
                 Thread.Sleep(150); // ~6-7 fps
             }
         }
-        catch { /* Pipe nicht verfügbar oder Timeout → Exit */ }
+        catch { /* Verbindung fehlgeschlagen → Exit */ }
     }
 }