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/i18n/locales/en.json

@@ -1867,7 +1867,7 @@
     }
   },
   "profiles": {
-    "switcherTooltip": "Projects: switch providers / MCP / Skills / memory files for Claude Code and Codex in one click",
+    "switcherTooltip": "Projects: switch providers / MCP / Skills / memory files for Claude Code and Codex, plus the Claude Desktop provider, in one click",
     "none": "No project",
     "searchPlaceholder": "Search projects",
     "empty": "No projects yet",

src/i18n/locales/ja.json

@@ -1867,7 +1867,7 @@
     }
   },
   "profiles": {
-    "switcherTooltip": "プロジェクト：Claude Code と Codex のプロバイダー / MCP / Skills / メモリファイルをワンクリックで切り替え",
+    "switcherTooltip": "プロジェクト：Claude Code と Codex のプロバイダー / MCP / Skills / メモリファイル、および Claude Desktop のプロバイダーをワンクリックで切り替え",
     "none": "プロジェクトを使用しない",
     "searchPlaceholder": "プロジェクトを検索",
     "empty": "プロジェクトはまだありません",

src/i18n/locales/zh-TW.json

@@ -1839,7 +1839,7 @@
     }
   },
   "profiles": {
-    "switcherTooltip": "專案：一鍵切換 Claude Code 與 Codex 的供應商 / MCP / Skills / 記憶檔案",
+    "switcherTooltip": "專案：一鍵切換 Claude Code 與 Codex 的供應商 / MCP / Skills / 記憶檔案，及 Claude Desktop 的供應商",
     "none": "不使用專案",
     "searchPlaceholder": "搜尋專案",
     "empty": "尚無專案",

src/i18n/locales/zh.json

@@ -1867,7 +1867,7 @@
     }
   },
   "profiles": {
-    "switcherTooltip": "项目：一键切换 Claude Code 与 Codex 的供应商 / MCP / Skills / 记忆文件",
+    "switcherTooltip": "项目：一键切换 Claude Code 与 Codex 的供应商 / MCP / Skills / 记忆文件，及 Claude Desktop 的供应商",
     "none": "不使用项目",
     "searchPlaceholder": "搜索项目",
     "empty": "暂无项目",