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/components/input/DownloadButton.tsx

@@ -1,4 +1,4 @@
-import { Button, Icon, Tooltip, TooltipTrigger } from '@umami/react-zen';
+import { Button, Icon, Text, Tooltip, TooltipTrigger } from '@umami/react-zen';
 import Papa from 'papaparse';
 import { useMessages } from '@/components/hooks';
 import { Download } from '@/components/icons';
@@ -24,7 +24,9 @@ export function DownloadButton({
           <Download />
         </Icon>
       </Button>
-      <Tooltip>{formatMessage(labels.download)}</Tooltip>
+      <Tooltip>
+        <Text size="sm">{formatMessage(labels.download)}</Text>
+      </Tooltip>
     </TooltipTrigger>
   );
 }