- Add DashboardMetrics for tracking downloads/uploads/cache hits per registry
- Add ActivityLog for recent activity with bounded size (50 entries)
- Instrument Docker, npm, Maven, and Cargo handlers with metrics
- Add /api/ui/dashboard endpoint with global stats and activity
- Implement dark theme dashboard with real-time polling (5s interval)
- Add mount points table showing registry paths and proxy upstreams
- Hide sidebar on mobile, show hamburger menu
- Add slide-out drawer with overlay
- Touch-friendly tap targets
- Responsive padding and font sizes
- Replace anchor emoji with NORA logo (O as hole)