feat: 重构 usePWAInstall 逻辑，优化 iOS 设备检测和安装提示处理

src/composables/usePWAInstall.ts

@@ -3,39 +3,33 @@ interface BeforeInstallPromptEvent extends Event {
   userChoice: Promise<{ outcome: "accepted" | "dismissed" }>;
 }
 
-export function usePWAInstall() {
-  const deferredPrompt = ref<BeforeInstallPromptEvent | null>(null);
-  const canInstall = ref(false);
-  const isInstalled = ref(false);
+// 全局状态，在模块加载时就创建
+const deferredPrompt = ref<BeforeInstallPromptEvent | null>(null);
+const canInstall = ref(false);
+const isInstalled = ref(false);
 
-  // 检测是否是 iOS 设备
-  function isIOS() {
-    return /iPad|iPhone|iPod/.test(navigator.userAgent) && !(window as any).MSStream;
+// 检测是否是 iOS 设备
+function isIOS() {
+  return /iPad|iPhone|iPod/.test(navigator.userAgent) && !(window as any).MSStream;
+}
+
+// 检测是否是 iOS Safari（未安装）
+function isIOSSafari() {
+  return isIOS() && !(window.navigator as any).standalone;
+}
+
+// 在模块加载时就设置监听器（不等待组件挂载）
+if (typeof window !== "undefined") {
+  // 检查是否已安装
+  if (window.matchMedia("(display-mode: standalone)").matches) {
+    isInstalled.value = true;
+    console.log("[PWA] Already installed (standalone mode)");
   }
-
-  // 检测是否是 iOS Safari（未安装）
-  function isIOSSafari() {
-    return isIOS() && !(window.navigator as any).standalone;
+  else if ((window.navigator as any).standalone === true) {
+    isInstalled.value = true;
+    console.log("[PWA] Already installed (iOS standalone)");
   }
-
-  // 使用 onMounted 确保在客户端环境执行
-  onMounted(() => {
-    console.log("[PWA] usePWAInstall mounted");
-
-    // 检查是否已安装
-    if (window.matchMedia("(display-mode: standalone)").matches) {
-      isInstalled.value = true;
-      console.log("[PWA] Already installed (standalone mode)");
-      return;
-    }
-
-    // 检查 iOS Safari 独立模式
-    if ((window.navigator as any).standalone === true) {
-      isInstalled.value = true;
-      console.log("[PWA] Already installed (iOS standalone)");
-      return;
-    }
-
+  else {
     // 监听安装提示事件（仅 Android/Chrome）
     window.addEventListener("beforeinstallprompt", (e: Event) => {
       console.log("[PWA] beforeinstallprompt event fired");
@@ -57,6 +51,14 @@ export function usePWAInstall() {
       console.log("[PWA] iOS Safari detected, showing install button");
       canInstall.value = true;
     }
+  }
+}
+
+export function usePWAInstall() {
+  onMounted(() => {
+    console.log("[PWA] usePWAInstall mounted");
+    console.log("[PWA] canInstall:", canInstall.value);
+    console.log("[PWA] isInstalled:", isInstalled.value);
   });
 
   async function install() {