feat: packet capture, bandwidth test (v0.11.5 Beta)

- Packet capture: RouterOS sniffer + SFTP download to PCAP for Wireshark analysis
- Bandwidth test: RouterOS /tool/bandwidth-test with TX/RX Mbps result display
- Both exposed in the Tools tab on device detail pages

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

backend/package.json

@@ -1,6 +1,6 @@
 {
   "name": "mikrotik-manager-backend",
-  "version": "0.11.4-beta",
+  "version": "0.11.5-beta",
   "description": "Mikrotik Network Management Platform - Backend API",
   "main": "dist/index.js",
   "scripts": {