Enhance VocabService and VocabLessonView for review lesson functionality

- Added logic in VocabService to retrieve vocabulary and lessons from previous lessons for review sessions, improving the learning experience.
- Implemented methods to gather review lessons and vocabulary exercises, ensuring users have access to relevant content during review lessons.
- Updated VocabLessonView to utilize review vocabulary exercises when in a review lesson, enhancing vocabulary extraction and user feedback.
- Improved console logging for better insights into the vocabulary processing flow, aiding in debugging and user interaction.

frontend/src/views/social/VocabLessonView.vue

@@ -390,14 +390,33 @@ export default {
     importantVocab() {
       // Extrahiere wichtige Begriffe aus den Übungen
       try {
+        // Bei Wiederholungslektionen: Verwende Vokabeln aus vorherigen Lektionen
+        if (this.lesson && (this.lesson.lessonType === 'review' || this.lesson.lessonType === 'vocab_review')) {
+          if (this.lesson.reviewVocabExercises && Array.isArray(this.lesson.reviewVocabExercises)) {
+            console.log('[importantVocab] Wiederholungslektion - verwende reviewVocabExercises:', this.lesson.reviewVocabExercises.length);
+            return this._extractVocabFromExercises(this.lesson.reviewVocabExercises);
+          } else {
+            console.log('[importantVocab] Wiederholungslektion aber keine reviewVocabExercises vorhanden');
+            return [];
+          }
+        }
+        
+        // Normale Lektion: Verwende Übungen aus der aktuellen Lektion
         if (!this.lesson || !this.lesson.grammarExercises || !Array.isArray(this.lesson.grammarExercises)) {
           console.log('[importantVocab] Keine Übungen vorhanden');
           return [];
         }
         
-        const vocabMap = new Map();
-        
-        this.lesson.grammarExercises.forEach((exercise, idx) => {
+        return this._extractVocabFromExercises(this.lesson.grammarExercises);
+      } catch (e) {
+        console.error('Fehler in importantVocab computed property:', e);
+        return [];
+      }
+    },
+    _extractVocabFromExercises(exercises) {
+      const vocabMap = new Map();
+      
+      exercises.forEach((exercise, idx) => {
           try {
             console.log(`[importantVocab] Verarbeite Übung ${idx + 1}:`, exercise.title);
             // Extrahiere aus questionData
@@ -469,15 +488,11 @@ export default {
           } catch (e) {
             console.warn('Fehler beim Extrahieren von Vokabeln aus Übung:', e, exercise);
           }
-        });
-        
-        const result = Array.from(vocabMap.values());
-        console.log(`[importantVocab] Ergebnis:`, result);
-        return result;
-      } catch (e) {
-        console.error('Fehler in importantVocab computed property:', e);
-        return [];
-      }
+      });
+      
+      const result = Array.from(vocabMap.values());
+      console.log(`[_extractVocabFromExercises] Ergebnis:`, result.length, 'Vokabeln');
+      return result;
     }
   },
   watch: {