refine: 删除按钮移到编辑弹窗 — 统一操作入口

- 表格行内只保留「编辑」按钮
- 编辑弹窗左下角红色「删除用户」按钮(仅支局长可见)
- 避免表格行内误删

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

frontend/src/views/desktop/UserManage.vue

@@ -98,10 +98,9 @@ async function handleDelete(row: any) {
             <span v-else style="color:var(--c-text-muted);font-size:12px">未绑定</span>
           </template>
         </el-table-column>
-        <el-table-column label="操作" width="130" fixed="right">
+        <el-table-column label="操作" width="80" fixed="right">
           <template #default="{ row }">
             <el-button text size="small" type="primary" @click="openEdit(row)">编辑</el-button>
-            <el-button v-if="auth.isDirector" text size="small" type="danger" @click="handleDelete(row)">删除</el-button>
           </template>
         </el-table-column>
       </el-table>
@@ -128,8 +127,13 @@ async function handleDelete(row: any) {
         </el-form>
       </template>
       <template #footer>
+        <div style="display:flex;justify-content:space-between;width:100%">
+          <el-button v-if="auth.isDirector" type="danger" @click="handleDelete(editUser)">删除用户</el-button>
+          <div>
             <el-button @click="editDialogVisible = false">取消</el-button>
             <el-button type="primary" @click="handleSave">保存</el-button>
+          </div>
+        </div>
       </template>
     </el-dialog>
   </div>