feat: 新增 BbSelect 组件，实现下拉选择功能

apps/extension/src/options/pages/ImportExportPage.vue

@@ -8,6 +8,10 @@ const file = ref(null);
 const status = ref("");
 const error = ref("");
 
+function onFileChange(e) {
+  file.value = e?.target?.files?.[0] || null;
+}
+
 async function importToLocal() {
   status.value = "";
   error.value = "";
@@ -44,8 +48,30 @@ async function importFile() {
   }
 }
 
-function exportCloud() {
-  window.open("http://localhost:3001/bookmarks/export/html", "_blank");
+async function exportCloud() {
+  status.value = "";
+  error.value = "";
+
+  try {
+    const html = await apiFetch("/bookmarks/export/html", {
+      method: "GET",
+      headers: { Accept: "text/html" }
+    });
+
+    const blob = new Blob([html], { type: "text/html;charset=utf-8" });
+    const url = URL.createObjectURL(blob);
+    const a = document.createElement("a");
+    a.href = url;
+    a.download = "bookmarks-cloud.html";
+    document.body.appendChild(a);
+    a.click();
+    a.remove();
+    URL.revokeObjectURL(url);
+
+    status.value = "云端导出完成";
+  } catch (e) {
+    error.value = e.message || String(e);
+  }
 }
 
 async function exportLocal() {
@@ -82,7 +108,7 @@ async function exportLocal() {
       <input
         type="file"
         accept="text/html,.html"
-        @change="(e) => (file.value = e.target.files?.[0] || null)"
+        @change="onFileChange"
       />
       <button class="btn" @click="importFile">开始导入</button>
       <p v-if="status" class="ok">{{ status }}</p>