Add Remote Desktop screen selector + new-tab button (v2.2.0)

- CaptureModeRunner: screen index param (0=all, 1-N=specific monitor)
- RtcService: reads screen from rdp_start JSON, passes to capture helper
- Program.cs: parses optional screen index arg for --rdp-capture
- RemoteDesktopPanel: screen dropdown (Alle/1-4), new-tab button
- RdpPage: fullscreen standalone page at /rdp/:agentId
- AgentDetailPage: removed dead _RemoteDesktopOld_unused code

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

agent-cs/CaptureModeRunner.cs

@@ -11,7 +11,7 @@ public static class CaptureModeRunner
     private static readonly ImageCodecInfo JpegCodec =
         ImageCodecInfo.GetImageEncoders().First(c => c.FormatID == ImageFormat.Jpeg.Guid);
 
-    public static void Run(string portStr)
+    public static void Run(string portStr, int screenIdx = 0)
     {
         if (!int.TryParse(portStr, out var port) || port <= 0) return;
 
@@ -24,22 +24,29 @@ public static class CaptureModeRunner
             var encParams = new EncoderParameters(1);
             encParams.Param[0] = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, 60L);
 
-            // Alle Screens zusammenführen (Multi-Monitor-Support)
+            // Capture-Region bestimmen: 0 = alle Screens, 1-N = spezifischer Screen
             var allScreens = System.Windows.Forms.Screen.AllScreens;
-            int left = allScreens.Min(s => s.Bounds.X);
-            int top = allScreens.Min(s => s.Bounds.Y);
-            int right = allScreens.Max(s => s.Bounds.X + s.Bounds.Width);
-            int bottom = allScreens.Max(s => s.Bounds.Y + s.Bounds.Height);
-            int totalW = right - left;
-            int totalH = bottom - top;
+            Rectangle captureRect;
+            if (screenIdx <= 0 || screenIdx > allScreens.Length)
+            {
+                int left = allScreens.Min(s => s.Bounds.X);
+                int top = allScreens.Min(s => s.Bounds.Y);
+                int right = allScreens.Max(s => s.Bounds.X + s.Bounds.Width);
+                int bottom = allScreens.Max(s => s.Bounds.Y + s.Bounds.Height);
+                captureRect = new Rectangle(left, top, right - left, bottom - top);
+            }
+            else
+            {
+                captureRect = allScreens[screenIdx - 1].Bounds;
+            }
 
             while (tcp.Connected)
             {
                 try
                 {
-                    using var bmp = new Bitmap(totalW, totalH, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
+                    using var bmp = new Bitmap(captureRect.Width, captureRect.Height, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
                     using (var g = Graphics.FromImage(bmp))
-                        g.CopyFromScreen(left, top, 0, 0, new Size(totalW, totalH));
+                        g.CopyFromScreen(captureRect.X, captureRect.Y, 0, 0, new Size(captureRect.Width, captureRect.Height));
 
                     byte[] jpeg;
                     using (var ms = new MemoryStream())

agent-cs/Program.cs

@@ -20,7 +20,9 @@ internal class Program
                     return;
 
                 case "--rdp-capture":
-                    CaptureModeRunner.Run(args.Length > 1 ? args[1] : "");
+                    CaptureModeRunner.Run(
+                        args.Length > 1 ? args[1] : "",
+                        args.Length > 2 && int.TryParse(args[2], out var si) ? si : 0);
                     return;
 
                 case "--dashboard":

agent-cs/Services/RtcService.cs

@@ -65,9 +65,10 @@ public class RtcService
 
             if (type == "rdp_start" && captureCts == null)
             {
+                var screenIdx = obj["screen"]?.ToObject<int>() ?? 0;
                 captureCts = CancellationTokenSource.CreateLinkedTokenSource(ct);
-                _ = CapturePipeLoopAsync(ws, captureCts.Token);
-                AgentWorker.Log("RDP: Screen-Capture gestartet");
+                _ = CapturePipeLoopAsync(ws, screenIdx, captureCts.Token);
+                AgentWorker.Log($"RDP: Screen-Capture gestartet (screen={screenIdx})");
             }
             else if (type == "rdp_stop" && captureCts != null)
             {
@@ -81,7 +82,7 @@ public class RtcService
         AgentWorker.Log("RDP: Getrennt");
     }
 
-    private async Task CapturePipeLoopAsync(ClientWebSocket ws, CancellationToken ct)
+    private async Task CapturePipeLoopAsync(ClientWebSocket ws, int screenIdx, CancellationToken ct)
     {
         var exePath = System.Diagnostics.Process.GetCurrentProcess().MainModule!.FileName;
 
@@ -90,7 +91,7 @@ public class RtcService
         listener.Start();
         var port = ((IPEndPoint)listener.LocalEndpoint).Port;
 
-        if (!SpawnCaptureHelper(exePath, port.ToString()))
+        if (!SpawnCaptureHelper(exePath, port.ToString(), screenIdx))
         {
             listener.Stop();
             AgentWorker.Log("RDP: Helper-Start fehlgeschlagen");
@@ -160,7 +161,7 @@ public class RtcService
         AgentWorker.Log("RDP: Frame-Loop beendet");
     }
 
-    private static bool SpawnCaptureHelper(string exePath, string portStr)
+    private static bool SpawnCaptureHelper(string exePath, string portStr, int screenIdx = 0)
     {
         try
         {
@@ -181,7 +182,7 @@ public class RtcService
                 ? "/ru \"INTERACTIVE\""
                 : $"/ru \"{fullUser}\"";
 
-            var args = $"/create /tn \"{taskName}\" /tr \"\\\"{exePath}\\\" --rdp-capture {portStr}\" " +
+            var args = $"/create /tn \"{taskName}\" /tr \"\\\"{exePath}\\\" --rdp-capture {portStr} {screenIdx}\" " +
                        $"/sc ONCE /st {triggerTime} {ruArg} /it /f";
 
             var p = Process.Start(new ProcessStartInfo("schtasks.exe", args)