sync last dev with cyr2lat

lib/services/background_service.dart

@@ -65,8 +65,7 @@ class BackgroundService {
         return AppLocalizations.delegate.load(overrideLocale);
       }
     }
-    final preferred =
-        WidgetsBinding.instance.platformDispatcher.locales;
+    final preferred = WidgetsBinding.instance.platformDispatcher.locales;
     final match = basicLocaleListResolution(preferred, supported);
     return AppLocalizations.delegate.load(match);
   }

lib/services/translation_service.dart

@@ -519,12 +519,11 @@ class TranslationService extends ChangeNotifier {
   }
 
   String? _heuristicLanguageCode(String text) {
-    if (RegExp(r'[іїєґІЇЄҐ]').hasMatch(text)) {
-      return 'uk';
-    }
-    if (RegExp(r'[а-яёА-ЯЁ]').hasMatch(text)) {
-      return 'ru';
+    final trimmed = text.trim();
+    if (trimmed.isEmpty) {
+      return null;
     }
+
     if (RegExp(r'[ぁ-んァ-ン]').hasMatch(text)) {
       return 'ja';
     }
@@ -534,9 +533,55 @@ class TranslationService extends ChangeNotifier {
     if (RegExp(r'[\u4e00-\u9fff]').hasMatch(text)) {
       return 'zh';
     }
-    // Latin-script languages can't be reliably distinguished by characters
-    // alone — return null so the translator always attempts translation.
-    return null;
+
+    final lower = trimmed.toLowerCase();
+    final patterns = <String, String>{
+      'uk': r'\b(привіт|дякую|будь|ласка|як|де|не|так|це|є|най|ще|може|для)\b',
+      'ru':
+          r'\b(что|это|как|не|да|нет|он|она|они|быть|есть|для|сегодня|если|уже|может)\b',
+      'bg': r'\b(ще|няма|благодаря|моля|това|какво|тук|ние|вие|не|със|за)\b',
+      'de':
+          r'\b(der|die|das|und|ist|nicht|ein|eine|ich|für|mit|auf|zu|auch|als|an|im|am|es|dem|den|sich|von)\b',
+      'en':
+          r'\b(the|and|is|you|for|with|from|not|that|this|have|be|are|was|were|but|can|will|your|what|when|how|they)\b',
+      'es':
+          r'\b(el|la|los|las|es|que|de|en|con|por|para|no|un|una|se|como|su|al|del|está)\b',
+      'fr':
+          r'\b(le|la|les|un|une|et|est|que|qui|pour|dans|pas|avec|sur|ne|vous|il|elle|des|ce|cette|je|tu|nous|vous)\b',
+      'it':
+          r'\b(il|la|lo|un|una|che|di|da|in|per|con|non|si|mi|ti|noi|voi|lui|lei)\b',
+      'pt':
+          r'\b(os|as|que|de|do|da|em|para|com|por|não|uma|um|se|você|também)\b',
+      'nl':
+          r'\b(de|het|een|en|is|niet|dat|wat|je|ik|op|aan|voor|met|als|nog|zijn)\b',
+      'sv':
+          r'\b(och|är|det|att|som|en|på|inte|har|var|men|du|jag|vi|ni|den|detta)\b',
+      'pl':
+          r'\b(na|się|nie|jest|to|że|do|od|dla|czy|tak|ale|ma|jak|on|ona|my)\b',
+      'sk': r'\b(je|na|so|že|do|od|za|si|to|ten|tá|tí|ako|má|nie|som|sa)\b',
+      'sl': r'\b(in|je|na|se|da|za|od|ne|to|ta|so|kako|bo|sem|si)\b',
+      'hu':
+          r'\b(az|és|nem|van|volt|hogy|mit|mire|ki|mi|ez|azért|is|de|ha|te|ő|mi|itt)\b',
+    };
+
+    final scores = <String, int>{};
+    for (final entry in patterns.entries) {
+      scores[entry.key] = RegExp(
+        entry.value,
+        caseSensitive: false,
+      ).allMatches(lower).length;
+    }
+
+    final sorted = scores.entries.toList()
+      ..sort((a, b) => b.value.compareTo(a.value));
+    if (sorted.isEmpty || sorted.first.value == 0) {
+      return null;
+    }
+    if (sorted.length > 1 && sorted.first.value == sorted[1].value) {
+      return null;
+    }
+
+    return sorted.first.key;
   }
 
   String _languageLabel(String code) {