feat(vocab): add dashboard learning summary and related endpoints

- Introduced `getDashboardLearningSummary` method in `VocabService` to provide a compact overview of enrolled courses and current lessons for users.
- Updated `vocabController` to include a new route for the dashboard widget, allowing users to access their learning summary.
- Enhanced `vocabRouter` to route requests for the new dashboard widget endpoint.
- Added localization support for the new dashboard features across multiple languages, improving user engagement and accessibility.
- Updated UI components to integrate the new dashboard widget, ensuring a seamless user experience.

backend/controllers/vocabController.js

@@ -48,7 +48,8 @@ class VocabController {
     this.enrollInCourse = this._wrapWithUser((userId, req) => this.service.enrollInCourse(userId, req.params.courseId), { successStatus: 201 });
     this.unenrollFromCourse = this._wrapWithUser((userId, req) => this.service.unenrollFromCourse(userId, req.params.courseId));
     this.getMyCourses = this._wrapWithUser((userId) => this.service.getMyCourses(userId));
-    
+    this.getDashboardLearningSummary = this._wrapWithUser((userId) => this.service.getDashboardLearningSummary(userId));
+
     // Progress
     this.getCourseProgress = this._wrapWithUser((userId, req) => this.service.getCourseProgress(userId, req.params.courseId));
     this.updateLessonProgress = this._wrapWithUser((userId, req) => this.service.updateLessonProgress(userId, req.params.lessonId, req.body));