Add Remote Desktop (JPEG-over-WebSocket), Agent v2.2.0

- RtcService.cs: Screen capture via Graphics.CopyFromScreen, ~8fps JPEG stream over WebSocket
- shellServer.js: Separate rdp-agent/rdp types with independent socket maps (no shell collision)
- AgentDetailPage: WebSocket-based RemoteDesktop component replaces WebRTC attempt
- setup.iss: Fixed filename to include 'v' prefix (IT-Nexus-Agent-Setup-v2.2.0.exe)
- Removed SIPSorcery dependencies, added System.Drawing.Common

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

backend/src/ws/shellServer.js

@@ -7,6 +7,10 @@ const agentSockets = new Map();
 // agentId -> WebSocket
 const browserSockets = new Map();
 
+// RDP: separate Maps damit Shell nicht kollidiert
+const rdpAgentSockets = new Map();
+const rdpBrowserSockets = new Map();
+
 function setupWebSocketServer(httpServer) {
     const wss = new WebSocket.Server({ server: httpServer, path: '/ws' });
 
@@ -24,6 +28,10 @@ function setupWebSocketServer(httpServer) {
             handleAgent(ws, url);
         } else if (type === 'shell') {
             handleBrowser(ws, url);
+        } else if (type === 'rdp-agent') {
+            handleRdpAgent(ws, url);
+        } else if (type === 'rdp') {
+            handleRdpBrowser(ws, url);
         } else {
             ws.close(1008, 'unknown type');
         }
@@ -124,6 +132,63 @@ function handleBrowser(ws, url) {
     });
 }
 
+function handleRdpAgent(ws, url) {
+    const key = url.searchParams.get('key');
+    if (key !== process.env.AGENT_API_KEY) { ws.close(1008, 'unauthorized'); return; }
+    const hostname = url.searchParams.get('hostname');
+    if (!hostname) { ws.close(1008, 'hostname required'); return; }
+
+    const db = getDatabase();
+    const agent = db.prepare('SELECT id FROM monitoring_agents WHERE hostname = ?').get(hostname);
+    if (!agent) { ws.close(1008, 'agent not found'); return; }
+
+    const agentId = agent.id;
+    const oldWs = rdpAgentSockets.get(agentId);
+    if (oldWs?.readyState === WebSocket.OPEN) oldWs.close();
+    rdpAgentSockets.set(agentId, ws);
+    console.log(`[WS-RDP] Agent verbunden: ${hostname}`);
+
+    ws.on('message', (data) => {
+        const bws = rdpBrowserSockets.get(agentId);
+        if (bws?.readyState === WebSocket.OPEN) bws.send(data.toString());
+    });
+
+    ws.on('close', () => {
+        rdpAgentSockets.delete(agentId);
+        const bws = rdpBrowserSockets.get(agentId);
+        if (bws?.readyState === WebSocket.OPEN) {
+            bws.send(JSON.stringify({ type: 'rdp_disconnected' }));
+        }
+        console.log(`[WS-RDP] Agent getrennt: ${hostname}`);
+    });
+}
+
+function handleRdpBrowser(ws, url) {
+    const token = url.searchParams.get('token');
+    try { jwt.verify(token, process.env.JWT_SECRET); }
+    catch { ws.close(1008, 'unauthorized'); return; }
+
+    const agentId = parseInt(url.searchParams.get('agentId'));
+    if (!agentId) { ws.close(1008, 'agentId required'); return; }
+
+    const oldBws = rdpBrowserSockets.get(agentId);
+    if (oldBws?.readyState === WebSocket.OPEN) oldBws.close();
+    rdpBrowserSockets.set(agentId, ws);
+
+    ws.on('message', (data) => {
+        const aws = rdpAgentSockets.get(agentId);
+        if (aws?.readyState === WebSocket.OPEN) aws.send(data.toString());
+    });
+
+    ws.on('close', () => {
+        rdpBrowserSockets.delete(agentId);
+        const aws = rdpAgentSockets.get(agentId);
+        if (aws?.readyState === WebSocket.OPEN) {
+            aws.send(JSON.stringify({ type: 'rdp_stop' }));
+        }
+    });
+}
+
 // Ankündigung an Agent pushen (für sofortige Zustellung)
 function pushAnnouncementToAgent(agentId, announcements) {
     const aws = agentSockets.get(agentId);