- Replace ToggleMapLayerAction with SelectMapLayerAction that takes a specific layer
- Update fireMapReducer to handle SelectMapLayerAction instead of toggling
- Use PopupMenuButton with GlobalKey to open menu on button tap
- Show check icon and bold text for currently selected layer
- Menu items display layer names: OSMC Grey, OSMC, Esri Street, Esri Satellite, Esri Terrain
- Selecting a layer immediately updates Redux state and closes the menu