fix(bisaya-course): update alternatives for transformation exercise

- Modified the alternatives for a transformation exercise to include additional variations, enhancing the response options for learners.
- Updated the vocabulary service to incorporate both primary and alternative answers, improving the accuracy of answer validation during exercises.

backend/scripts/create-bisaya-course-content.js

@@ -2026,7 +2026,7 @@ const BISAYA_EXERCISES = {
       answerData: {
         type: 'transformation',
         correct: 'Karon',
-        alternatives: ['Karong adlawa']
+        alternatives: ['Karong adlawa', 'Karong adlawa', 'Karong adlawa.']
       },
       explanation: '"karon" heißt „jetzt/heute“. „karong adlawa“ ist eine betonte Form für „heute“.'
     },

backend/services/vocabService.js

@@ -3622,9 +3622,13 @@ export default class VocabService {
         .some((answer) => answer === normalizedUser);
     }
 
-    // Für andere Typen: einfacher String-Vergleich (kann später erweitert werden)
-    const correctAnswers = parsedAnswerData.correct || parsedAnswerData.correctAnswer || [];
-    const correctAnswersArray = Array.isArray(correctAnswers) ? correctAnswers : [correctAnswers];
+    // Für andere Typen: einfacher String-Vergleich inkl. hinterlegter Alternativen
+    const primaryAnswers = parsedAnswerData.correct || parsedAnswerData.correctAnswer || [];
+    const primaryAnswersArray = Array.isArray(primaryAnswers) ? primaryAnswers : [primaryAnswers];
+    const alternativeAnswersArray = Array.isArray(parsedAnswerData.alternatives)
+      ? parsedAnswerData.alternatives
+      : [];
+    const correctAnswersArray = [...primaryAnswersArray, ...alternativeAnswersArray];
     const normalizedUserAnswer = this._normalizeTextAnswer(userAnswer);
     return correctAnswersArray.some(correct => this._normalizeTextAnswer(correct) === normalizedUserAnswer);
   }