Add Croatian and Slovenian localizations, implement locale preferences, and update settings screen

- Created `app_localizations_hr.dart` and `app_localizations_sl.dart` for Croatian and Slovenian translations.
- Added `app_sl.arb` file for Slovenian localization strings.
- Enhanced `main.dart` to support locale selection and initialization.
- Updated `home_screen.dart` and `settings_screen.dart` to handle locale changes and display current language.
- Implemented `locale_preferences.dart` service for managing locale settings using SharedPreferences.
- Modified `pubspec.yaml` to include `flutter_localizations` and enable localization file generation.

pubspec.yaml

@@ -30,6 +30,11 @@ environment:
 dependencies:
   flutter:
     sdk: flutter
+  flutter_localizations:
+    sdk: flutter
+
+  # Internationalization
+  intl: any
 
   # The following adds the Cupertino Icons font to your application.
   # Use with the CupertinoIcons class for iOS style icons.
@@ -90,6 +95,9 @@ flutter:
   # the material Icons class.
   uses-material-design: true
 
+  # Enable generation of localization files
+  generate: true
+
   # To add assets to your application, add an assets section, like this:
   # assets:
   #   - images/a_dot_burr.jpeg