Bump MapPin price font weight from 500 to 600

Medium (500) was too thin at 11px — semibold (600) reads better
while still being lighter than the name (700) for hierarchy.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/components/atoms/MapPin/MapPin.tsx

@@ -174,7 +174,7 @@ export const MapPin = React.forwardRef<HTMLDivElement, MapPinProps>(
               component="span"
               sx={{
                 fontSize: 11,
-                fontWeight: 500,
+                fontWeight: 600,
                 fontFamily: (t: Theme) => t.typography.fontFamily,
                 lineHeight: 1.2,
                 color: active ? palette.activePrice : palette.price,