fix(client): 默认 UI 品牌文案统一英文 Pangolin(窗口标题/托盘/安装包名/macOS 菜单栏)

默认 UI 语言是英文,但窗口标题(windowManager.setTitle)、MaterialApp title、
托盘 tooltip 与右键菜单、Windows 安装包显示名、macOS CFBundleName 硬编码中文,
中英混排。统一改英文品牌名;iOS 桌面图标名(CFBundleDisplayName=穿山甲)按
市场定位保留。托盘菜单文案后续可接 l10n(现契约无 tray 键)。

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FEVUXAbFT6bF1Qw27RHWoD

client/windows/installer/pangolin.iss

@@ -2,7 +2,7 @@
 ; 编译: ISCC.exe pangolin.iss  (或用 Inno Setup Compiler 打开)
 ; 前置: 先在 client/ 跑 `flutter build windows`(Release),产物在
 ;       ..\..\build\windows\x64\runner\Release
-#define MyAppName "穿山甲 Pangolin"
+#define MyAppName "Pangolin"
 #define MyAppVersion "1.0.73"
 #define MyAppPublisher "Pangolin"
 #define MyAppExeName "pangolin_vpn.exe"