feat(security): Security Center — firewall, NAT, bandwidth, posture, connections (v0.14.0-beta)

A dedicated top-level Security section plus a Meraki/UniFi-grade firewall built
on the full RouterOS feature set.

Security Center (new /security page)
- Fleet hardening scores, per-device posture list, and a "Common Findings"
  rollup aggregating identical issues across the fleet
- "Manage" deep-links into the device's Security tab (?tab= support added)

Firewall & NAT (per device + in Security Center)
- Friendly rule builder: Allow/Drop/Reject chips, Any/Address/Address-List
  pickers, port presets, connection-state chips, logging, live plain-English
  preview
- Address lists as reusable objects, referenced from rules
- Rule reordering (/ip/firewall/{filter,nat}/move); per-rule hit counters
  (print stats) with dead-rule highlighting + reset
- NAT wizards: Port Forward / Masquerade / 1:1 NAT + Custom
- Safe-apply lockout guard: backend 409 on an unscoped input drop/reject that
  would sever management; UI confirms before forcing (detectLockoutRisk, tested)

Access & security
- Security posture audit: graduated, de-duplicated scoring that never proposes
  disabling the management service the platform connects through (no self-
  lockout); switch-aware input-firewall severity; service hardening table
- Bandwidth: simple-queue CRUD + one-click "Limit this client" on client detail
- Active connections viewer

These L3 features are available on all managed RouterOS devices (routers,
switches, APs), not gated by device type.

Backend: DeviceCollector address-list/move/stats/connections/queues/service
methods; device routes for all of the above; firewallSafety + firewallSummary
utils with unit tests (19 new).

Security: bump nodemailer 8 -> 9.0.1 to clear GHSA-p6gq-j5cr-w38f (our
createTransport/sendMail usage is unaffected by the advisory's raw-option path).

Verified live against RouterOS devices; lint/typecheck/build/jest green in both
workspaces; npm audit --audit-level=high clean.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/App.tsx

@@ -26,6 +26,7 @@ import NetworkServicesWireGuardPage from './pages/NetworkServicesWireGuardPage';
 import NetworkServicesSyslogPage from './pages/NetworkServicesSyslogPage';
 import NetworkServicesNetflowPage from './pages/NetworkServicesNetflowPage';
 import TrafficAnalyticsPage from './pages/TrafficAnalyticsPage';
+import SecurityPage from './pages/SecurityPage';
 
 function ProtectedRoute({ children }: { children: React.ReactNode }) {
   const token = useAuthStore((s) => s.token);
@@ -71,6 +72,7 @@ export default function App() {
           <Route path="network-services/syslog" element={<NetworkServicesSyslogPage />} />
           <Route path="network-services/netflow" element={<NetworkServicesNetflowPage />} />
           <Route path="traffic" element={<TrafficAnalyticsPage />} />
+          <Route path="security" element={<SecurityPage />} />
         </Route>
         <Route path="*" element={<Navigate to="/dashboard" replace />} />
       </Routes>