feat: 添加API连接状态显示页脚

在应用底部添加固定页脚显示当前连接的API地址

ionic-app/src/App.vue

@@ -1,5 +1,15 @@
 <script setup lang="ts">
 import { IonApp, IonRouterOutlet } from '@ionic/vue'
+import { onMounted } from 'vue'
+
+const apiHost = import.meta.env.VITE_API_BASE_URL || 'http://localhost:3001'
+
+onMounted(() => {
+  const footer = document.getElementById('api-footer')
+  if (footer) {
+    footer.textContent = `连接: ${apiHost}`
+  }
+})
 </script>
 
 <template>