fix: resolve CodeQL security alerts (v0.11.10 Beta)

Log injection (3 errors fixed):
- errorHandler.ts: sanitize req.path before logging (strip \r\n)
- clients.ts: sanitize mac param in two Flux error log lines

Dismissed as false positives or won't-fix with justifications:
- Insecure Helmet config: CSP intentionally disabled (self-hosted,
  Vite/React inline styles require complex allowlist)
- Permissive CORS: wildcard only active when admin explicitly sets
  CORS_ORIGIN=*, documented as unsafe
- Network data to file (cert.ts x2): intentional cert upload feature
- File system race (oui.ts): trusted startup URL, no attack surface
- Insecure temp file (oui.ts): server-side OUI DB, not user-accessible
- Remote property injection (DeviceCollector.ts): data from trusted
  RouterOS API on admin-credentialed device, not user HTTP input
- Rate limiting (19): all routes behind JWT; login already rate-limited

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

backend/package.json

@@ -1,6 +1,6 @@
 {
   "name": "mikrotik-manager-backend",
-  "version": "0.11.9-beta",
+  "version": "0.11.10-beta",
   "description": "Mikrotik Network Management Platform - Backend API",
   "main": "dist/index.js",
   "scripts": {