feat(首页): 在课程卡片上添加已购标识

为已购买的课程添加视觉标识，方便用户快速识别

 <!--
  * @Date: 2025-03-20 19:55:21
  * @LastEditors: hookehuyr hookehuyr@gmail.com
- * @LastEditTime: 2025-09-25 11:54:13
+ * @LastEditTime: 2025-10-13 11:39:43
  * @FilePath: /mlaj/src/views/HomePage.vue
  * @Description: 美乐爱觉教育首页组件
  *
@@ -199,6 +199,14 @@
                   :alt="course.title"
                   class="w-full h-full object-cover"
                 />
+                <!-- 已购标识 -->
+                <div
+                  v-if="course.is_buy"
+                  class="absolute top-0 left-0 bg-orange-500 text-white text-xs px-2 py-1 rounded-br-lg font-medium"
+                  style="background-color: rgba(249, 115, 22, 0.85)"
+                >
+                  已购
+                </div>
                 <div class="absolute inset-0 bg-gradient-to-b from-transparent via-black/20 to-black/60 flex flex-col justify-end p-4">
                   <div class="bg-amber-500/90 text-white px-2 py-1 rounded-full text-xs font-medium inline-block w-fit mb-1">
                     {{ course.category }}
@@ -300,12 +308,20 @@
                 class="p-3 rounded-xl"
               >
                 <div class="flex flex-col h-full" @click="goToCourseDetail(item)">
-                  <div class="h-28 mb-2 rounded-lg overflow-hidden">
+                  <div class="h-28 mb-2 rounded-lg overflow-hidden relative">
                     <img
                       :src="item.cover || 'https://cdn.ipadbiz.cn/mlaj/images/default_block.png'"
                       :alt="item.title"
                       class="w-full h-full object-cover"
                     />
+                    <!-- 已购标识 -->
+                    <div
+                      v-if="item.is_buy"
+                      class="absolute top-0 left-0 bg-orange-500 text-white text-xs px-2 py-1 rounded-br-lg font-medium"
+                      style="background-color: rgba(249, 115, 22, 0.85)"
+                    >
+                      已购
+                    </div>
                   </div>
                   <h4 class="font-medium text-sm mb-1 line-clamp-1">{{ item.title }}</h4>
                   <!--<p class="text-xs text-gray-500 flex items-center mt-auto">
@@ -521,7 +537,7 @@ import ActivityCard from '@/components/ui/ActivityCard.vue'
 import SummerCampCard from '@/components/ui/SummerCampCard.vue'
 import VideoPlayer from '@/components/ui/VideoPlayer.vue'
 
-// 导入模拟数据和工具函数
+// TODO: 导入模拟数据和工具函数
 import { liveStreams, activities } from '@/utils/mockData'
 import { useTitle } from '@vueuse/core'
 import { useAuth } from '@/contexts/auth'