- Convert registry list, docker detail, package detail, maven detail pages to dark theme
- Use layout_dark instead of layout for all pages
- Update colors: bg-[#1e293b] cards, slate-700 borders, slate-200/400 text
- Mark unused light theme functions with #[allow(dead_code)]
- 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)