Rename SideMenu to NavMenu, fix tooltips, and update react-zen.

- Rename SideMenu to NavMenu with visible group title labels and selected item highlighting
- Update react-zen to 0.242.0 and fix responsive breakpoints (xs -> base)
- Style floating tooltips with inverted background across WorldMap, charts, and WeeklyTraffic
- Add CSS variables for primary color and use IconLabel consistently
- Remove stray console.log from LoadingPanel

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/app/(main)/admin/AdminLayout.tsx

@@ -13,9 +13,9 @@ export function AdminLayout({ children }: { children: ReactNode }) {
   }
 
   return (
-    <Grid columns={{ xs: '1fr', lg: 'auto 1fr' }} width="100%" height="100%">
+    <Grid columns={{ base: '1fr', lg: 'auto 1fr' }} width="100%" height="100%">
       <Column
-        display={{ xs: 'none', lg: 'flex' }}
+        display={{ base: 'none', lg: 'flex' }}
         width="240px"
         height="100%"
         border="right"