feat: cleanup SignalR — supprimer anciens adaptateurs (closes #7)

- Supprimé connection-manager.js, websocket-adapter.js,
  rest-socket-adapter.js, cti-simulator.js
- Retiré @microsoft/signalr de package.json
- Seul socketio-adapter.js reste comme couche de communication

package.json

@@ -86,7 +86,6 @@
     "url": "https://github.com/simpleconnect/electron-app.git"
   },
   "dependencies": {
-    "@microsoft/signalr": "^9.0.6",
     "choices.js": "^11.1.0",
     "socket.io-client": "^4.8.1"
   }