refactor(vocab): standardize text normalization methods in VocabService and VocabLessonView

- Updated text normalization logic in VocabService to use a regex that replaces punctuation with spaces, improving text handling consistency.
- Refactored VocabLessonView to utilize the new normalization method for comparable text, enhancing the accuracy of user input processing.
- Ensured both components now share a unified approach to text normalization, streamlining code and improving maintainability.

backend/services/vocabService.js

@@ -345,7 +345,7 @@ export default class VocabService {
     return String(text || '')
       .trim()
       .toLowerCase()
-      .replace(/[.,!?;:¿¡"]/g, '')
+      .replace(/[\p{P}]+/gu, ' ')
       .replace(/\s+/g, ' ');
   }
 
@@ -2689,7 +2689,7 @@ export default class VocabService {
       const correctTexts = correctIndices
         .map((i) => options[i])
         .filter((opt) => opt !== undefined && opt !== null);
-      const norm = (s) => String(s).trim().toLowerCase();
+      const norm = (s) => this._normalizeTextAnswer(s);
 
       // Nach zufälligen Distraktoren: Client sendet gewählten Optionstext statt Index
       if (typeof userAnswer === 'string') {

frontend/src/views/social/VocabLessonView.vue

@@ -2041,7 +2041,7 @@ export default {
       const totalSlots = options.length;
       const need = totalSlots - correctTexts.length;
       if (need <= 0) return null;
-      const norm = (s) => String(s).trim().toLowerCase();
+      const norm = (s) => this.normalizeComparableText(s);
       const correctSet = new Set(correctTexts.map(norm));
       const poolRaw = side === 'target' ? this.distractorPool.target : this.distractorPool.native;
       let poolFiltered = poolRaw.filter((w) => w && !correctSet.has(norm(w)));
@@ -2700,8 +2700,15 @@ export default {
         this.checkVocabAnswer();
       }
     },
+    normalizeComparableText(value) {
+      return String(value || '')
+        .trim()
+        .toLowerCase()
+        .replace(/[\p{P}]+/gu, ' ')
+        .replace(/\s+/g, ' ');
+    },
     normalizeVocab(s) {
-      return String(s || '').trim().toLowerCase().replace(/\s+/g, ' ');
+      return this.normalizeComparableText(s);
     },
     checkVocabAnswer() {
       if (!this.currentVocabQuestion) return;