feat(mcp): add import button to import MCP servers from apps

- Add import_mcp_from_apps command that reuses existing import logic
- Add Import button in MCP panel header (consistent with Skills)
- Fix import count to only return truly new servers (not already in DB)
- Update translations for import success/no-import messages (zh/en/ja)

src/i18n/locales/en.json

@@ -565,6 +565,7 @@
   },
   "mcp": {
     "title": "MCP Management",
+    "import": "Import",
     "claudeTitle": "Claude Code MCP Management",
     "codexTitle": "Codex MCP Management",
     "geminiTitle": "Gemini MCP Management",
@@ -576,6 +577,8 @@
       "deleteConfirm": "Are you sure you want to delete server \"{{id}}\"? This action cannot be undone.",
       "noServers": "No servers yet",
       "enabledApps": "Enabled Apps",
+      "noImportFound": "No MCP servers to import found. All servers are already managed by CC Switch.",
+      "importSuccess": "Successfully imported {{count}} MCP servers",
       "apps": {
         "claude": "Claude",
         "codex": "Codex",

src/i18n/locales/ja.json

@@ -565,6 +565,7 @@
   },
   "mcp": {
     "title": "MCP 管理",
+    "import": "インポート",
     "claudeTitle": "Claude Code MCP 管理",
     "codexTitle": "Codex MCP 管理",
     "geminiTitle": "Gemini MCP 管理",
@@ -576,6 +577,8 @@
       "deleteConfirm": "サーバー「{{id}}」を削除しますか？この操作は元に戻せません。",
       "noServers": "まだサーバーがありません",
       "enabledApps": "有効なアプリ",
+      "noImportFound": "インポートする MCP サーバーが見つかりませんでした。すべてのサーバーは CC Switch で管理されています。",
+      "importSuccess": "{{count}} 個の MCP サーバーをインポートしました",
       "apps": {
         "claude": "Claude",
         "codex": "Codex",

src/i18n/locales/zh.json

@@ -565,6 +565,7 @@
   },
   "mcp": {
     "title": "MCP 管理",
+    "import": "导入",
     "claudeTitle": "Claude Code MCP 管理",
     "codexTitle": "Codex MCP 管理",
     "geminiTitle": "Gemini MCP 管理",
@@ -576,6 +577,8 @@
       "deleteConfirm": "确定要删除服务器 \"{{id}}\" 吗？此操作无法撤销。",
       "noServers": "暂无服务器",
       "enabledApps": "启用的应用",
+      "noImportFound": "未发现需要导入的 MCP 服务器。所有服务器已在 CC Switch 统一管理中。",
+      "importSuccess": "成功导入 {{count}} 个 MCP 服务器",
       "apps": {
         "claude": "Claude",
         "codex": "Codex",