fix(know-your-world): actually change magnifier element dimensions to 1/3

The previous commit only updated calculation variables but missed the
actual rendered element's CSS. This fixes:

- Change magnifier element width from '50%' to use MAGNIFIER_SIZE_RATIO
- Change from aspectRatio: '2/1' to explicit height using MAGNIFIER_SIZE_RATIO
- Now magnifier is truly 1/3 width and 1/3 height of container

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

apps/web/src/arcade-games/know-your-world/components/MapRenderer.tsx

@@ -2291,8 +2291,8 @@ export function MapRenderer({
               // Animated positioning - smoothly moves to opposite corner from cursor
               top: magnifierSpring.top,
               left: magnifierSpring.left,
-              width: '50%',
+              width: `${MAGNIFIER_SIZE_RATIO * 100}%`,
-              aspectRatio: '2/1',
+              height: `${MAGNIFIER_SIZE_RATIO * 100}%`,
               // High zoom (>60x) gets gold border, normal zoom gets blue border
               border: zoomSpring.to(
                 (zoom: number) =>