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-survival-sentences-exercises.js

@@ -13,6 +13,31 @@ import VocabCourseLesson from '../models/community/vocab_course_lesson.js';
 import VocabGrammarExercise from '../models/community/vocab_grammar_exercise.js';
 import User from '../models/community/user.js';
 
+function normalizeMcAnswerLanguage(question = '') {
+  const q = String(question || '').trim();
+  if (!q) return null;
+  if (/Wie sagt man/i.test(q) || /auf Bisaya\?/i.test(q)) return 'target';
+  if (/Was bedeutet/i.test(q) || /Was heißt/i.test(q)) return 'native';
+  return null;
+}
+
+function enrichAnswerLanguage(exercises = []) {
+  return exercises.map((exercise) => {
+    const qd = exercise?.questionData;
+    if (!qd || qd.type !== 'multiple_choice') return exercise;
+    if (qd.answerLanguage || qd.answerLanguageId) return exercise;
+    const inferred = normalizeMcAnswerLanguage(qd.question);
+    if (!inferred) return exercise;
+    return {
+      ...exercise,
+      questionData: {
+        ...qd,
+        answerLanguage: inferred
+      }
+    };
+  });
+}
+
 // Spezifische Übungen für Überlebenssätze
 const SURVIVAL_EXERCISES = {
   'Überlebenssätze - Teil 1': [
@@ -399,7 +424,7 @@ async function updateSurvivalExercises() {
     console.log(`   ${lessons.length} "Überlebenssätze"-Lektionen gefunden\n`);
 
     for (const lesson of lessons) {
-      const exercises = SURVIVAL_EXERCISES[lesson.title];
+      const exercises = enrichAnswerLanguage(SURVIVAL_EXERCISES[lesson.title]);
       
       if (!exercises || exercises.length === 0) {
         console.log(`   ⚠️  Lektion ${lesson.lessonNumber}: "${lesson.title}" - keine Übungen definiert`);