feat: Implement course discovery page with category sidebar filtering.

Frontend-Learner/pages/classroom/learning.vue

@@ -411,8 +411,14 @@ const performSaveProgress = async (force: boolean = false, keepalive: boolean =
         const isCompletedNow = res.success && (res.data?.is_completed || progressPercentage >= 0.95)
 
         if (isCompletedNow) {
+             const wasAlreadyCompleted = lesson.progress?.is_completed
              markLessonAsCompletedLocally(lesson.id)
              if (lesson.progress) lesson.progress.is_completed = true
+             
+             // If newly completed, reload course data to unlock next lesson in sidebar
+             if (!wasAlreadyCompleted) {
+                 await loadCourseData()
+             }
         }
     } catch (err) {
         console.error('Save progress failed', err)