feat(l10n): add Arabic and English translations for update URL error message

- Add Arabic translation for "couldNotOpenUpdateUrl" message in app_ar.arb
- Add English translation for "couldNotOpenUpdateUrl" message in app_en.arb
- Include description and placeholder for the new translation entries

Author: fulleni

lib/l10n/app_localizations.dart

@@ -1705,6 +1705,12 @@ abstract class AppLocalizations {
   /// In en, this message translates to:
   /// **'Suggested Sources'**
   String get suggestedSourcesTitle;
+
+  /// Message displayed in a snackbar when the update URL cannot be opened.
+  ///
+  /// In en, this message translates to:
+  /// **'Could not open update URL: {url}'**
+  String couldNotOpenUpdateUrl(String url);
 }
 
 class _AppLocalizationsDelegate

lib/l10n/app_localizations_ar.dart

@@ -889,4 +889,9 @@ class AppLocalizationsAr extends AppLocalizations {
 
   @override
   String get suggestedSourcesTitle => 'مصادر مقترحة';
+
+  @override
+  String couldNotOpenUpdateUrl(String url) {
+    return 'تعذر فتح رابط التحديث: $url';
+  }
 }

lib/l10n/app_localizations_en.dart

@@ -891,4 +891,9 @@ class AppLocalizationsEn extends AppLocalizations {
 
   @override
   String get suggestedSourcesTitle => 'Suggested Sources';
+
+  @override
+  String couldNotOpenUpdateUrl(String url) {
+    return 'Could not open update URL: $url';
+  }
 }

lib/l10n/arb/app_ar.arb

@@ -1160,5 +1160,14 @@
     "suggestedSourcesTitle": "مصادر مقترحة",
     "@suggestedSourcesTitle": {
         "description": "عنوان لمجموعة المصادر المقترحة."
+    },
+    "couldNotOpenUpdateUrl": "تعذر فتح رابط التحديث: {url}",
+    "@couldNotOpenUpdateUrl": {
+        "description": "رسالة تظهر في شريط الإشعارات عندما يتعذر فتح رابط التحديث.",
+        "placeholders": {
+            "url": {
+                "type": "String"
+            }
+        }
     }
 }

lib/l10n/arb/app_en.arb

@@ -1160,5 +1160,14 @@
     "suggestedSourcesTitle": "Suggested Sources",
     "@suggestedSourcesTitle": {
         "description": "Title for the suggested sources content collection."
+    },
+    "couldNotOpenUpdateUrl": "Could not open update URL: {url}",
+    "@couldNotOpenUpdateUrl": {
+        "description": "Message displayed in a snackbar when the update URL cannot be opened.",
+        "placeholders": {
+            "url": {
+                "type": "String"
+            }
+        }
     }
 }