feat(vocab): update course today plan localization and UI logic

- Added new localization strings for scenarios with no due reviews in German, English, and Spanish, enhancing user guidance.
- Updated VocabCourseView to conditionally display the appropriate introduction message based on the presence of due reviews, improving clarity in the course flow.

frontend/src/views/social/VocabLessonReviewView.vue

@@ -3,7 +3,7 @@
     <section class="surface-card review-header">
       <button type="button" class="button-secondary" @click="backToCourse">{{ $t('general.back') }}</button>
       <div>
-        <h2>Kurz-Wiederholung</h2>
+        <h2>{{ $t('socialnetwork.vocab.courses.quickReviewTitle') }}</h2>
         <p v-if="lesson">{{ lesson.title }} (#{{ lesson.lessonNumber }})</p>
       </div>
     </section>
@@ -12,17 +12,17 @@
     <section v-else-if="!lesson" class="surface-card review-state">{{ $t('socialnetwork.vocab.notFound') }}</section>
     <section v-else class="surface-card review-body">
       <p class="review-intro">
-        Kurze Session mit {{ reviewQueue.length }} Begriffen. Nach Abschluss wird die geplante Wiederholung als erledigt markiert.
+        {{ $t('socialnetwork.vocab.courses.quickReviewIntro', { count: reviewQueue.length }) }}
       </p>
 
       <div v-if="reviewDone" class="review-done">
-        <h3>Geschafft</h3>
-        <p>Richtig: {{ correctCount }} / {{ reviewQueue.length }}</p>
-        <button type="button" @click="backToCourse">Zurück zum Kurs</button>
+        <h3>{{ $t('socialnetwork.vocab.courses.quickReviewDoneTitle') }}</h3>
+        <p>{{ $t('socialnetwork.vocab.courses.quickReviewDoneScore', { correct: correctCount, total: reviewQueue.length }) }}</p>
+        <button type="button" @click="backToCourse">{{ $t('socialnetwork.vocab.courses.quickReviewBackToCourse') }}</button>
       </div>
 
       <div v-else-if="currentItem" class="review-card">
-        <p class="review-progress">Begriff {{ currentIndex + 1 }} von {{ reviewQueue.length }}</p>
+        <p class="review-progress">{{ $t('socialnetwork.vocab.courses.quickReviewProgress', { current: currentIndex + 1, total: reviewQueue.length }) }}</p>
         <p class="review-question">{{ currentPrompt }}</p>
 
         <div v-if="mode === 'multiple_choice'" class="review-options">
@@ -55,7 +55,7 @@
             class="button-secondary"
             @click="advanceAfterFeedback"
           >
-            Gelesen, weiter
+            {{ $t('socialnetwork.vocab.courses.quickReviewAcknowledge') }}
           </button>
         </div>
 
@@ -101,8 +101,8 @@ export default {
     currentPrompt() {
       if (!this.currentItem) return '';
       return this.mode === 'multiple_choice'
-        ? `Was bedeutet "${this.currentItem.target}"?`
-        : `Tippe auf Zielsprache: "${this.currentItem.gloss}"`;
+        ? this.$t('socialnetwork.vocab.courses.quickReviewPromptMeaning', { term: this.currentItem.target })
+        : this.$t('socialnetwork.vocab.courses.quickReviewPromptTarget', { term: this.currentItem.gloss });
     },
     submitDisabled() {
       if (!this.currentItem) return true;