feat: Introduce comprehensive course management features for admin, including recommended, pending, and detailed course views, and instructor course listing with a lesson preview component.

frontend_management/pages/admin/courses/[id].vue

@@ -212,12 +212,16 @@
             กรุณาระบุเหตุผลในการปฏิเสธคอร์ส "{{ course?.title.th }}"
           </p>
           <q-input
+            ref="rejectInputRef"
             v-model="rejectReason"
             type="textarea"
             outlined
             rows="4"
             label="เหตุผล *"
-            :rules="[val => !!val || 'กรุณาระบุเหตุผล']"
+            :rules="[
+              val => !!val || 'กรุณาระบุเหตุผล',
+              val => (val && val.length >= 10) || 'ระบุเหตุผลอย่างน้อย 10 ตัวอักษร'
+            ]"
             hide-bottom-space
             lazy-rules="ondemand"
           />
@@ -229,7 +233,6 @@
             label="ยืนยันการปฏิเสธ"
             color="negative"
             :loading="actionLoading"
-            :disable="!rejectReason.trim()"
             @click="confirmReject"
           />
         </q-card-actions>
@@ -239,7 +242,7 @@
 </template>
 
 <script setup lang="ts">
-import { useQuasar } from 'quasar';
+import { useQuasar, QInput } from 'quasar';
 import { adminService, type CourseDetailForReview } from '~/services/admin.service';
 
 definePageMeta({
@@ -258,6 +261,7 @@ const error = ref('');
 const actionLoading = ref(false);
 const showRejectModal = ref(false);
 const rejectReason = ref('');
+const rejectInputRef = ref<QInput | null>(null);
 
 // Computed
 const totalLessons = computed(() => 
@@ -415,7 +419,8 @@ const confirmApprove = () => {
 };
 
 const confirmReject = async () => {
-  if (!course.value || !rejectReason.value.trim()) return;
+  rejectInputRef.value?.validate();
+  if (rejectInputRef.value?.hasError || !course.value) return;
   
   actionLoading.value = true;
   try {