feat: multiple translations with context, improved task examples

- Add WordTranslation model for storing multiple translations per word
- AI generates translations with example sentences and their translations
- Show example usage after answering tasks (learning + interface language)
- Save translations to word_translations table when adding words from tasks
- Improve word exclusion in new_words mode (stronger prompt + client filtering)
- Add migration for word_translations table

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

bot/handlers/tasks.py

@@ -109,6 +109,18 @@ async def start_new_words_tasks(callback: CallbackQuery, state: FSMContext):
         # Показываем индикатор загрузки
         await callback.message.edit_text(t(lang, 'tasks.generating_new'))
 
+        # Получаем слова для исключения:
+        # 1. Все слова из словаря пользователя
+        vocab_words = await VocabularyService.get_all_user_word_strings(
+            session, user.id, learning_lang=user.learning_language
+        )
+        # 2. Слова из предыдущих заданий new_words, на которые ответили правильно
+        correct_task_words = await TaskService.get_correctly_answered_words(
+            session, user.id
+        )
+        # Объединяем списки исключений
+        exclude_words = list(set(vocab_words + correct_task_words))
+
         # Генерируем новые слова через AI
         words = await ai_service.generate_thematic_words(
             theme="random everyday vocabulary",
@@ -116,6 +128,7 @@ async def start_new_words_tasks(callback: CallbackQuery, state: FSMContext):
             count=5,
             learning_lang=user.learning_language,
             translation_lang=user.language_interface,
+            exclude_words=exclude_words if exclude_words else None,
         )
 
         if not words:
@@ -132,7 +145,9 @@ async def start_new_words_tasks(callback: CallbackQuery, state: FSMContext):
                 'question': f"{translate_prompt}: {word.get('word', '')}",
                 'word': word.get('word', ''),
                 'correct_answer': word.get('translation', ''),
-                'transcription': word.get('transcription', '')
+                'transcription': word.get('transcription', ''),
+                'example': word.get('example', ''),  # Пример на изучаемом языке
+                'example_translation': word.get('example_translation', '')  # Перевод примера
             })
 
         await state.update_data(
@@ -226,6 +241,16 @@ async def process_answer(message: Message, state: FSMContext):
     if feedback:
         result_text += f"💬 {feedback}\n\n"
 
+    # Показываем пример использования если есть
+    example = task.get('example', '')
+    example_translation = task.get('example_translation', '')
+    if example:
+        result_text += f"📖 {t(lang, 'tasks.example_label')}:\n"
+        result_text += f"<i>{example}</i>\n"
+        if example_translation:
+            result_text += f"<i>({example_translation})</i>\n"
+        result_text += "\n"
+
     # Сохраняем результат в БД
     async with async_session_maker() as session:
         await TaskService.save_task_result(
@@ -298,6 +323,8 @@ async def add_task_word(callback: CallbackQuery, state: FSMContext):
     word = task.get('word', '')
     translation = task.get('correct_answer', '')
     transcription = task.get('transcription', '')
+    example = task.get('example', '')  # Пример использования как контекст
+    example_translation = task.get('example_translation', '')  # Перевод примера
 
     async with async_session_maker() as session:
         user = await UserService.get_user_by_telegram_id(session, callback.from_user.id)
@@ -316,7 +343,7 @@ async def add_task_word(callback: CallbackQuery, state: FSMContext):
             return
 
         # Добавляем слово в словарь
-        await VocabularyService.add_word(
+        new_word = await VocabularyService.add_word(
             session=session,
             user_id=user.id,
             word_original=word,
@@ -327,6 +354,18 @@ async def add_task_word(callback: CallbackQuery, state: FSMContext):
             source=WordSource.AI_TASK
         )
 
+        # Сохраняем перевод в таблицу word_translations
+        await VocabularyService.add_translations_bulk(
+            session=session,
+            vocabulary_id=new_word.id,
+            translations=[{
+                'translation': translation,
+                'context': example if example else None,
+                'context_translation': example_translation if example_translation else None,
+                'is_primary': True
+            }]
+        )
+
     await callback.answer(t(lang, 'tasks.word_added', word=word), show_alert=True)