fix: update localStorage key for AI exam task management to ensure consistency across components

Author: gainsborouo

frontend/src/components/GenerateAIExamModal.vue

@@ -349,7 +349,7 @@ const apiKeyStatus = ref({ has_api_key: false, api_key_masked: null })
 const apiKeyForm = ref({ key: '' })
 const apiKeyLoading = ref(false)
 
-const TASK_STORAGE_KEY = 'ai_exam_current_task'
+const TASK_STORAGE_KEY = 'aiExamCurrentTask'
 
 const form = ref({
   category: null,

frontend/src/components/Navbar.vue

@@ -458,6 +458,7 @@ export default {
       sessionStorage.removeItem('authToken')
       localStorage.removeItem('selectedSubject')
       localStorage.removeItem('adminCurrentTab')
+      localStorage.removeItem('aiExamCurrentTask')
       this.isAuthenticated = false
       this.userData = null