- Add bg-surface background to roast stats, consumption, and country pill cards
- Update tab CSS: bg-surface background, hover:border-accent/40 instead of bg-surface-alt
- Add hover:border-accent/40 to clickable country pill buttons
- Make Roasts the first and default tab on the stats page
- Add --highlight-rgb CSS custom property for light and dark themes
- Add MutationObserver to world-map for theme change detection
- Read choropleth colors from CSS custom properties instead of hardcoded values
- Simplify stats_map partial to use text-highlight class
- New /stats page with Roasters, Roasts, Cups, and Cafes tabs
- Interactive choropleth world map (SVG) colored by country counts
- Clickable country chips that highlight individual countries on the map
- Horizontal chip scroller with chevron navigation on desktop
- Datastar-powered tab switching without page reload
- Domain layer: country name → ISO code mapping, flag emoji generation
- StatsRepository trait with four aggregate SQL queries
- <world-map> and <chip-scroll> custom elements for Datastar compatibility
