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.lock

@@ -246,6 +246,11 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "6.0.0"
+  flutter_localizations:
+    dependency: "direct main"
+    description: flutter
+    source: sdk
+    version: "0.0.0"
   flutter_map:
     dependency: "direct main"
     description:
@@ -361,7 +366,7 @@ packages:
     source: hosted
     version: "4.1.2"
   intl:
-    dependency: transitive
+    dependency: "direct main"
     description:
       name: intl
       sha256: "3df61194eb431efc39c4ceba583b95633a403f46c9fd341e550ce0bfa50e9aa5"