Add: Agent v2.1.2, WebSocket Live Shell, WebRTC Remote Desktop (Beta), Announcement Push

- Agent v2.1.2: WebSocket ShellService, ACK nach WS-Ankündigungen, shown_announcements Fix
- Backend: shellServer.js mit WebSocket-Server (Shell + Announcement Push + RTC Signaling)
- Backend: patch.controller.js Fix (command_id=0 Falsy-Bug beim Auto-Update)
- Frontend: Remote Desktop Tab (WebRTC Beta) in AgentDetailPage für super_admin/admin
- Frontend: PatchManagementPage auf v2.1.2 aktualisiert
- WPF Notification: AllowsTransparency=False + kein DropShadowEffect (Dispatcher-Crash Fix)

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

backend/package.json

@@ -16,29 +16,30 @@
   "author": "",
   "license": "ISC",
   "dependencies": {
+    "@anthropic-ai/sdk": "^0.39.0",
     "bcrypt": "^5.1.1",
     "better-sqlite3": "^12.6.2",
+    "botbuilder": "^4.23.3",
     "bwip-js": "^4.8.0",
-    "imapflow": "^1.0.0",
-    "node-cron": "^3.0.0",
-    "nodemailer": "^6.9.0",
     "cors": "^2.8.5",
     "dotenv": "^16.3.1",
     "express": "^4.18.2",
     "express-rate-limit": "^7.1.5",
     "express-validator": "^7.0.1",
     "helmet": "^7.1.0",
+    "imapflow": "^1.0.0",
     "jsonwebtoken": "^9.0.2",
+    "mailparser": "^3.7.1",
+    "mammoth": "^1.8.0",
     "morgan": "^1.10.0",
+    "multer": "^1.4.5-lts.1",
+    "net-snmp": "^3.11.0",
+    "node-cron": "^3.0.0",
+    "nodemailer": "^6.9.0",
+    "pdf-parse": "^1.1.1",
     "pdfkit": "^0.15.0",
     "qrcode": "^1.5.4",
-    "@anthropic-ai/sdk": "^0.39.0",
-    "botbuilder": "^4.23.3",
-    "pdf-parse": "^1.1.1",
-    "mammoth": "^1.8.0",
-    "mailparser": "^3.7.1",
-    "net-snmp": "^3.11.0",
-    "multer": "^1.4.5-lts.1"
+    "ws": "^8.21.0"
   },
   "devDependencies": {
     "nodemon": "^3.0.2"