fix: 修复记录筛选不生效和avatar资源报错

- 添加dateRange的deep watcher,日期变化时自动重新查询
- 修复快捷日期按钮(今天/近7天/本月)设置后未触发查询的问题
- 移除不存在的avatars/admin.jpg默认头像,改用空字符串使用fallback

frontend/src/components/admin-sidebar/index.vue

@@ -12,7 +12,7 @@ const { t } = useI18n()
 const user = reactive({
   name: t('nav.admin'),
   email: 'admin@example.com',
-  avatar: '/avatars/admin.jpg',
+  avatar: '',
   role: 'admin',
 })
 

frontend/src/pages/admin/cloud-variables/[id]/records.vue

@@ -278,6 +278,11 @@ watch([page, pageSize], () => {
   fetchRecords()
 })
 
+watch(dateRange, () => {
+  page.value = 1
+  fetchRecords()
+}, { deep: true })
+
 async function fetchVariable() {
   try {
     const data = await api.get<{ variables: Variable[] }>(`/dev/cloud-variables?app_id=${route.query.app_id}`)