fix: resolve CrowdSec state sync issues and remove deprecated mode toggle

- Backend: Start/Stop handlers now sync both settings and security_configs tables
- Frontend: CrowdSec toggle uses actual process status (crowdsecStatus.running)
- Frontend: Fixed LiveLogViewer WebSocket race condition by using isPausedRef
- Frontend: Removed deprecated mode toggle from CrowdSecConfig page
- Frontend: Added info banner directing users to Security Dashboard
- Frontend: Added "Start CrowdSec" button to enrollment warning panel

Fixes dual-source state conflict causing toggle to show incorrect state.
Fixes live log "disconnected" status appearing while logs stream.
Simplifies CrowdSec control to single source (Security Dashboard toggle).

Includes comprehensive test updates for new architecture.

frontend/src/pages/__tests__/Security.dashboard.test.tsx

@@ -263,6 +263,8 @@ describe('Security Dashboard - Card Status Tests', () => {
   describe('SD-08: Threat Protection Summaries', () => {
     it('should display threat protection descriptions for each card', async () => {
       vi.mocked(securityApi.getSecurityStatus).mockResolvedValue(mockSecurityStatusAllEnabled)
+      // CrowdSec must be running to show threat protection descriptions
+      vi.mocked(crowdsecApi.statusCrowdsec).mockResolvedValue({ running: true, pid: 1234, lapi_ready: true })
 
       await renderSecurityPage()