feat: Add localization for edit headline feature

- Added new strings to localizations
- Supports 'Edit Headline' screen
- Includes success/error messages

Author: fulleni

lib/l10n/app_localizations.dart

@@ -1213,6 +1213,36 @@ abstract class AppLocalizations {
   /// In en, this message translates to:
   /// **'Other'**
   String get sourceTypeOther;
+
+  /// Title for the Edit Headline page
+  ///
+  /// In en, this message translates to:
+  /// **'Edit Headline'**
+  String get editHeadline;
+
+  /// Message displayed when a headline is updated successfully
+  ///
+  /// In en, this message translates to:
+  /// **'Headline updated successfully.'**
+  String get headlineUpdatedSuccessfully;
+
+  /// Message displayed while loading headline data
+  ///
+  /// In en, this message translates to:
+  /// **'Loading Headline...'**
+  String get loadingHeadline;
+
+  /// Label for an image URL input field
+  ///
+  /// In en, this message translates to:
+  /// **'Image URL'**
+  String get imageUrl;
+
+  /// Error message when updating a headline fails because the original data wasn't loaded
+  ///
+  /// In en, this message translates to:
+  /// **'Cannot update: Original headline data not loaded.'**
+  String get cannotUpdateHeadlineError;
 }
 
 class _AppLocalizationsDelegate

lib/l10n/app_localizations_ar.dart

@@ -634,4 +634,20 @@ class AppLocalizationsAr extends AppLocalizations {
 
   @override
   String get sourceTypeOther => 'أخرى';
+
+  @override
+  String get editHeadline => 'تعديل العنوان';
+
+  @override
+  String get headlineUpdatedSuccessfully => 'تم تحديث العنوان بنجاح.';
+
+  @override
+  String get loadingHeadline => 'جاري تحميل العنوان...';
+
+  @override
+  String get imageUrl => 'رابط الصورة';
+
+  @override
+  String get cannotUpdateHeadlineError =>
+      'لا يمكن التحديث: لم يتم تحميل بيانات العنوان الأصلية.';
 }

lib/l10n/app_localizations_en.dart

@@ -632,4 +632,20 @@ class AppLocalizationsEn extends AppLocalizations {
 
   @override
   String get sourceTypeOther => 'Other';
+
+  @override
+  String get editHeadline => 'Edit Headline';
+
+  @override
+  String get headlineUpdatedSuccessfully => 'Headline updated successfully.';
+
+  @override
+  String get loadingHeadline => 'Loading Headline...';
+
+  @override
+  String get imageUrl => 'Image URL';
+
+  @override
+  String get cannotUpdateHeadlineError =>
+      'Cannot update: Original headline data not loaded.';
 }