refactor(exercises): standardize answer language handling across exercise scripts

- Introduced a mechanism to infer answer language based on question phrasing in multiple exercise scripts, enhancing consistency in exercise data.
- Updated question formats to clarify the intent of exercises, improving user understanding and engagement.
- Streamlined the code for better maintainability and clarity in exercise generation processes.

backend/scripts/update-family-words-exercises.js

@@ -134,6 +134,7 @@ function createFamilyWordsExercises(nativeLanguageName) {
       instruction: 'Wähle die richtige Übersetzung.',
       questionData: {
         type: 'multiple_choice',
+        answerLanguage: 'target',
         question: `Wie sagt man "${nativeWord}" auf Bisaya?`,
         options: options
       },