Add Android support with configurable server URL and location permissions

- Add shared_preferences for persisting server URL
- Add SettingsService and PlatformService
- Add server URL input field on non-web platforms
- Make ApiConfig baseUrl configurable at runtime
- Add Android location permissions (ACCESS_FINE/COURSE_LOCATION, INTERNET)
- Request location permission on login and map init
- Fix geo_id type: use String instead of int (UUID format)
- Align share_service with API spec: remove unique_id, use share_id only
- Fix watch endpoint response: last_update instead of created_at
- Add error handling with SnackBars for geo operations
- Wrap login screen in SingleChildScrollView for keyboard handling
- Update map tile layer with userAgentPackageName for OSM

android/app/src/main/AndroidManifest.xml

@@ -1,4 +1,8 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android">
+    <uses-permission android:name="android.permission.INTERNET" />
+    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
+    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
+
     <application
         android:label="family_safety_frontend"
         android:name="${applicationName}"