feat(profiles): include Claude Desktop provider in project profiles

Claude Desktop's only dimension managed by cc-switch is its provider
(MCP/Skills are hardcoded unsupported and prompts have no live file),
so snapshots capture just the current desktop provider while the empty
MCP/Skills sets and None prompt make apply a natural no-op for the
other dimensions - no per-dimension special casing needed.

- Add claude-desktop slot to PROFILE_APPS and PerApp (serde key uses
  the hyphenated app id); old payloads without the key deserialize to
  None and leave Claude Desktop untouched on apply
- Gate the tray Projects submenu by iterating PROFILE_APPS instead of
  hardcoding Claude/Codex visibility
- Show the profile switcher on the Claude Desktop tab, mirror the
  PerApp type, invalidate the claude-desktop providers cache on apply,
  and extend the switcher tooltip in all four locales
- Extend the roundtrip integration test with the desktop provider
  dimension; the desktop switch is cfg-gated to macOS/Windows because
  desktop live writes error on Linux where CI runs cargo test

src/components/profiles/ProfileSwitcher.tsx

@@ -42,7 +42,7 @@ import {
 import { ProfileManageDialog } from "./ProfileManageDialog";
 
 /** 后端 services/profile.rs 的 PROFILE_APPS 前端镜像，扩展支持范围时两处同步 */
-const PROFILE_SUPPORTED_APPS: AppId[] = ["claude", "codex"];
+const PROFILE_SUPPORTED_APPS: AppId[] = ["claude", "claude-desktop", "codex"];
 
 interface ProfileSwitcherProps {
   activeApp: AppId;
@@ -51,8 +51,8 @@ interface ProfileSwitcherProps {
 /**
  * 项目 Profile 切换器（header 左侧入口）
  *
- * Profile 是跨应用的配置快照（Claude Code + Codex 的供应商/MCP/Skills/记忆文件），
- * 与右侧 AppSwitcher（仅切换查看的应用）语义不同。
+ * Profile 是跨应用的配置快照（Claude Code + Codex 的供应商/MCP/Skills/记忆文件，
+ * 以及 Claude Desktop 的供应商），与右侧 AppSwitcher（仅切换查看的应用）语义不同。
  */
 export function ProfileSwitcher({ activeApp }: ProfileSwitcherProps) {
   const { t } = useTranslation();
@@ -66,7 +66,7 @@ export function ProfileSwitcher({ activeApp }: ProfileSwitcherProps) {
   const clearMutation = useClearProfileMutation();
   const createMutation = useCreateProfileMutation();
 
-  // Profile 仅作用于 Claude Code + Codex——在其他应用的标签页展示会误导用户
+  // Profile 仅作用于受支持的应用——在其他应用的标签页展示会误导用户
   // 以为当前应用也被切换了，因此只在受支持应用的页面渲染
   if (!PROFILE_SUPPORTED_APPS.includes(activeApp)) {
     return null;