fix(frontend): auto-attach admin api keys and normalize admin list payloads

src/pages/admin/MembersPage.vue

@@ -40,10 +40,12 @@ async function load() {
   error.value = false
   try {
     const res = await getMembers()
-    members.value = res.data || []
+    members.value = res.data?.items || []
   } catch (err) {
     error.value = true
-    errorMsg.value = '載入失敗，請稍後再試'
+    errorMsg.value = err.response?.status === 422
+      ? '缺少管理員 API 認證，請檢查前端 .env.development'
+      : '載入失敗，請稍後再試'
   } finally {
     loading.value = false
   }