feat: localisation with en, de, fr and it

lib/core/services/optimized_storage_service.dart

@@ -23,6 +23,7 @@ class OptimizedStorageService {
   static const String _activeServerIdKey = 'active_server_id';
   static const String _rememberCredentialsKey = 'remember_credentials';
   static const String _themeModeKey = 'theme_mode';
+  static const String _localeCodeKey = 'locale_code_v1';
   static const String _localConversationsKey = 'local_conversations';
   static const String _onboardingSeenKey = 'onboarding_seen_v1';
   static const String _reviewerModeKey = 'reviewer_mode_v1';
@@ -226,6 +227,20 @@ class OptimizedStorageService {
     await _prefs.setString(_themeModeKey, mode);
   }
 
+  /// Locale Management
+  String? getLocaleCode() {
+    // Returns a locale code like 'en', 'de', 'fr', 'it'. Null means system.
+    return _prefs.getString(_localeCodeKey);
+  }
+
+  Future<void> setLocaleCode(String? code) async {
+    if (code == null || code.isEmpty) {
+      await _prefs.remove(_localeCodeKey);
+    } else {
+      await _prefs.setString(_localeCodeKey, code);
+    }
+  }
+
   /// Onboarding
   Future<bool> getOnboardingSeen() async {
     return _prefs.getBool(_onboardingSeenKey) ?? false;

lib/core/services/user_friendly_error_handler.dart

@@ -182,12 +182,12 @@ class UserFriendlyErrorHandler {
   List<ErrorRecoveryAction> _getServerRecoveryActions() {
     return [
       ErrorRecoveryAction(
-        label: 'Try Again',
+        label: 'Retry',
         action: ErrorActionType.retry,
         description: 'Retry your request',
       ),
       ErrorRecoveryAction(
-        label: 'Wait & Retry',
+        label: 'Retry',
         action: ErrorActionType.retryLater,
         description: 'Wait a moment then try again',
       ),
@@ -223,7 +223,7 @@ class UserFriendlyErrorHandler {
         description: 'Sign in to your account',
       ),
       ErrorRecoveryAction(
-        label: 'Try Again',
+        label: 'Retry',
         action: ErrorActionType.retry,
         description: 'Retry the request',
       ),
@@ -280,7 +280,7 @@ class UserFriendlyErrorHandler {
         description: 'Select another file',
       ),
       ErrorRecoveryAction(
-        label: 'Try Again',
+        label: 'Retry',
         action: ErrorActionType.retry,
         description: 'Retry the operation',
       ),
@@ -314,7 +314,7 @@ class UserFriendlyErrorHandler {
         description: 'Open app settings to grant permissions',
       ),
       ErrorRecoveryAction(
-        label: 'Try Again',
+        label: 'Retry',
         action: ErrorActionType.retry,
         description: 'Retry after granting permission',
       ),
@@ -324,7 +324,7 @@ class UserFriendlyErrorHandler {
   List<ErrorRecoveryAction> _getGenericRecoveryActions() {
     return [
       ErrorRecoveryAction(
-        label: 'Try Again',
+        label: 'Retry',
         action: ErrorActionType.retry,
         description: 'Retry the operation',
       ),