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.

lib/services/locale_preferences.dart

@@ -0,0 +1,70 @@
+import 'package:flutter/material.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+
+/// Service for managing locale preferences
+class LocalePreferences {
+  static const String _localeKey = 'app_locale';
+
+  /// Supported locales
+  static const List<Locale> supportedLocales = [
+    Locale('en'), // English
+    Locale('sl'), // Slovenian
+    Locale('hr'), // Croatian
+  ];
+
+  /// Get the saved locale or return null to use system locale
+  static Future<Locale?> getLocale() async {
+    final prefs = await SharedPreferences.getInstance();
+    final localeCode = prefs.getString(_localeKey);
+
+    if (localeCode == null) {
+      return null; // Use system locale
+    }
+
+    return Locale(localeCode);
+  }
+
+  /// Save the selected locale
+  static Future<void> setLocale(Locale? locale) async {
+    final prefs = await SharedPreferences.getInstance();
+
+    if (locale == null) {
+      // Remove preference to use system locale
+      await prefs.remove(_localeKey);
+    } else {
+      await prefs.setString(_localeKey, locale.languageCode);
+    }
+  }
+
+  /// Get display name for a locale
+  static String getDisplayName(Locale? locale) {
+    if (locale == null) {
+      return 'System Default';
+    }
+
+    switch (locale.languageCode) {
+      case 'en':
+        return 'English';
+      case 'sl':
+        return 'Slovenščina';
+      case 'hr':
+        return 'Hrvatski';
+      default:
+        return locale.languageCode;
+    }
+  }
+
+  /// Get native display name for a locale (shown in selection dialog)
+  static String getNativeDisplayName(Locale locale) {
+    switch (locale.languageCode) {
+      case 'en':
+        return 'English';
+      case 'sl':
+        return 'Slovenščina';
+      case 'hr':
+        return 'Hrvatski';
+      default:
+        return locale.languageCode;
+    }
+  }
+}