feat: add NPM and Authentik sections to Control Room navigation
- Add ControlRoomNav enum with section grouping (Portainer, NPM, Authentik)
- Update NavPanel to support conditional section headers
- Rename NavSection to NavItem with optional section field
- Add routes for NPM: Proxy Hosts, Redirections, Streams, SSL Certificates
- Add routes for Authentik: Users, Groups, Applications
- Section headers auto-show when multiple sections exist
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Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
