- Implement handleASDetail() and handlePrefixDetail() HTML handlers
- Create AS detail HTML template with prefix listings
- Create prefix detail HTML template with route information
- Add timeSince template function for human-readable durations
- Update templates.go to include new templates
- Server-side rendered pages as requested (no client-side API calls)
- Move all handler functions to handlers.go
- Move setupRoutes to routes.go
- Clean up server.go to only contain core server logic
- Add missing GetASDetails and GetPrefixDetails to mockStore for tests
- Fix linter errors (magic numbers, unused parameters, blank lines)
