fix(frontend): 改进订阅状态实时刷新机制

- 在 Dashboard 页面加载时强制刷新订阅状态
- 在兑换订阅卡密后立即刷新订阅状态
- 清理订阅轮询相关注释

frontend/src/views/user/DashboardView.vue

@@ -661,6 +661,7 @@ import { ref, computed, onMounted, watch } from 'vue'
 import { useRouter } from 'vue-router'
 import { useI18n } from 'vue-i18n'
 import { useAuthStore } from '@/stores/auth'
+import { useSubscriptionStore } from '@/stores/subscriptions'
 import { formatDateTime } from '@/utils/format'
 
 const { t } = useI18n()
@@ -701,6 +702,7 @@ ChartJS.register(
 
 const router = useRouter()
 const authStore = useAuthStore()
+const subscriptionStore = useSubscriptionStore()
 
 const user = computed(() => authStore.user)
 const stats = ref<UserDashboardStats | null>(null)
@@ -1018,6 +1020,11 @@ onMounted(async () => {
   // Load critical data first
   await loadDashboardStats()
 
+  // Force refresh subscription status when entering dashboard (bypass cache)
+  subscriptionStore.fetchActiveSubscriptions(true).catch((error) => {
+    console.error('Failed to refresh subscription status:', error)
+  })
+
   // Initialize date range (synchronous)
   initializeDateRange()