Add ExpandedMapScreen and integrate it into navigation; enhance CacheCardItem and GameSettingsScreen with improved UI elements

src/utils/geoMath.js

@@ -1,5 +1,11 @@
 import * as geolib from 'geolib';
 
+// Convert raw Magnetometer {x, y} reading to a 0-360° heading
+const toHeading = ({x, y}) => {
+  const angle = Math.atan2(y, x) * (180 / Math.PI);
+  return angle < 0 ? angle + 360 : angle;
+};
+
 const isWithinRadius = (playerCoords, cacheCoords, radius) => {
   const distance = geolib.getDistance(playerCoords, cacheCoords);
   return distance <= radius;
@@ -14,5 +20,5 @@ const isLookingAtCache = (playerHeading, playerCoords, cacheCoords, tolerance =
   return diff <= tolerance || diff >= 360 - tolerance;
 };
 
-export { isWithinRadius, isLookingAtCache };
+export { toHeading, isWithinRadius, isLookingAtCache };