fix: wrap DigitalEmployeeFactory and GoalDetail with MainLayout

Both pages were missing the MainLayout wrapper, causing the navigation
bar to disappear when navigating to /digital-employees or /goals/:id.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/views/DigitalEmployeeFactory.vue

@@ -1,4 +1,5 @@
 <template>
+  <MainLayout>
   <div class="digital-employee-factory">
     <div class="page-header">
       <div>
@@ -78,9 +79,11 @@
       </template>
     </el-dialog>
   </div>
+  </MainLayout>
 </template>
 
 <script setup lang="ts">
+import MainLayout from '@/components/MainLayout.vue'
 import { ref, reactive, onMounted } from 'vue'
 import { useRouter } from 'vue-router'
 import { ElMessage } from 'element-plus'

frontend/src/views/GoalDetail.vue

@@ -1,4 +1,5 @@
 <template>
+  <MainLayout>
   <div class="goal-detail" v-loading="loading">
     <!-- 顶部栏 -->
     <div class="detail-header">
@@ -123,9 +124,11 @@
       </div>
     </el-card>
   </div>
+  </MainLayout>
 </template>
 
 <script setup lang="ts">
+import MainLayout from '@/components/MainLayout.vue'
 import { ref, computed, onMounted, onUnmounted } from 'vue'
 import { useRoute, useRouter } from 'vue-router'
 import { ElMessage, ElMessageBox } from 'element-plus'