fix: reactively apply dark mode on Android when system theme changes

[lodev09]

Summary

React Native prevents Activity recreation on configuration changes (android:configChanges), so Google Maps' MapColorScheme.FOLLOW_SYSTEM never gets notified when the device toggles dark mode. This registers a ComponentCallbacks2 listener on the application context to detect UI mode changes and re-apply the map color scheme.

Closes #47

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation update

Test Plan

• Set theme="system" on MapView
• Toggle device dark mode from system settings
• Map should reactively switch between light and dark styles without remounting

Checklist

• I tested on iOS
• I tested on Android
• I tested on Web
• I updated the documentation (if needed)