fix: 桌面端编辑时客户名称显示UUID的问题

WorkPlans/MiniBusiness/KeyVisits/ManagerWorkspace 四个页面的
openEdit 均直接 spread item 到 form，未确保客户在 el-select
选项列表中。修复：编辑前检查并补充客户到 customers 列表。

Co-Authored-By: Claude <noreply@anthropic.com>

frontend/src/views/desktop/ManagerWorkspace.vue

@@ -104,6 +104,9 @@ function openCreate(type: string) {
 function openEdit(type: string, item: any) {
   dialogMode.value = 'edit'; dialogType.value = type
   form.value = { ...item }
+  if (item.customer_id && item.customer_name && !customers.value.find((c: any) => c.id === item.customer_id)) {
+    customers.value.unshift({ id: item.customer_id, name: item.customer_name })
+  }
   dialogTimeRange.value = null
   if ((type === 'visit' || type === 'note') && item.time_range && item.time_range.includes('-')) {
     const parts = item.time_range.split('-')