feat(desktop): 稳定桌面端界面与文件操作反馈

- 重构 DesktopPreferences 为分栏式设置面板，整合连接、外观、通知、更新与诊断信息分区，并补充过渡动效与暗色主题样式
- DesktopLayout 侧边栏导航分组支持展开折叠，调整管理/项目区块顺序并统一图标与标题
- 新增 fileTaskFeedback 工具，统一 pickFiles/saveFile/openFile 的成功/取消提示，替换审计导出、权限日志、附件、文档、线程、项目配置等处的直接调用
- desktopUpdateManager 暴露更新状态快照与状态变更监听，区分检查中、安装中、已推迟、失败等状态
- DesktopServerSettings 增加连接诊断信息（检查时间、健康地址、耗时、HTTP 状态）
- unified-page.css 与 ProjectMilestones 引入 CSS 变量以适配暗色主题
- WebLayout 将服务器设置入口改为打开系统偏好面板，管理菜单中邮件服务归入系统设置分组
- ProfileSettings 移除已迁入偏好面板的桌面端专属区块
- 补充 Layout.desktop 布局与偏好面板契约测试

frontend/src/components/attachments/AttachmentList.vue

@@ -152,7 +152,8 @@ import { displayDateTime, getUserDisplayName } from "../../utils/display";
 import { getAttachmentPermissionKey } from "../../utils/attachmentPermissions";
 import { isApiPermissionAllowed } from "../../utils/apiPermissionValue";
 import { TEXT } from "../../locales";
-import { clientRuntime, openFile, pickFiles, saveFile } from "../../runtime";
+import { clientRuntime } from "../../runtime";
+import { openFileWithFeedback, pickFilesWithFeedback, saveFileWithFeedback } from "../../utils/fileTaskFeedback";
 
 type AttachmentEntityGroup = {
   entityType: string;
@@ -280,7 +281,7 @@ const queuePendingUpload = (fileType: string, uploadFile: any) => {
 
 const pickPendingNative = async (group: UploadGroup) => {
   if (!canUploadGroup(group)) return;
-  const selected = await pickFiles({ multiple: true, title: group.label });
+  const selected = await pickFilesWithFeedback({ multiple: true, title: group.label });
   selected.forEach((file) => queuePendingFile(group.key, file));
 };
 
@@ -351,7 +352,7 @@ const uploadImmediate = async (options: any) => {
 };
 
 const pickImmediateNative = async () => {
-  const [file] = await pickFiles({ multiple: false, title: headerTitle.value });
+  const [file] = await pickFilesWithFeedback({ multiple: false, title: headerTitle.value });
   if (file) await uploadImmediate({ file });
 };
 
@@ -399,7 +400,7 @@ const fetchAttachmentBlob = async (row: any): Promise<Blob> => {
 
 const download = async (row: any) => {
   try {
-    await saveFile({
+    await saveFileWithFeedback({
       suggestedName: row?.filename || "download",
       mimeType: row?.content_type,
       data: await fetchAttachmentBlob(row),
@@ -411,7 +412,7 @@ const download = async (row: any) => {
 
 const openExternally = async (row: any) => {
   try {
-    await openFile({
+    await openFileWithFeedback({
       suggestedName: row?.filename || "attachment",
       mimeType: row?.content_type,
       data: await fetchAttachmentBlob(row),