feat: Add i18n support with English and Thai locales and implement the new classroom learning page with course curriculum and video playback.

Frontend-Learner/pages/classroom/learning.vue

@@ -17,6 +17,7 @@ useHead({
 })
 
 const route = useRoute()
+const router = useRouter()
 const { t } = useI18n()
 const { user } = useAuth()
 const { fetchCourseLearningInfo, fetchLessonContent, saveVideoProgress, markLessonComplete, checkLessonAccess, fetchVideoProgress } = useCourse()
@@ -415,8 +416,26 @@ const onVideoEnded = async () => {
         const res = await markLessonComplete(courseId.value, currentLesson.value.id)
         if (res.success) {
              markLessonAsCompletedLocally(currentLesson.value.id)
+             
+             // If course completed
              if (res.data.is_course_completed) {
-                  alert("ยินดีด้วย! คุณเรียนจบหลักสูตรแล้ว")
+                  // Refresh course data to update certificate status
+                  await loadCourseData()
+                  alert(t('course.completed') || "ยินดีด้วย! คุณเรียนจบหลักสูตรแล้ว")
+             } else if (res.data.next_lesson_id) {
+                 // Suggest next lesson
+                 if (confirm(t('common.next') + '?')) {
+                     const nextId = res.data.next_lesson_id
+                     
+                     // Update URL without reload if possible, but router.push is standard
+                     await router.push({
+                        path: '/classroom/learning',
+                        query: { ...route.query, lesson_id: nextId }
+                     })
+                     
+                     // Manually load the lesson since we don't have a watcher on query
+                     handleLessonSelect(nextId)
+                 }
              }
         }
     }