✨ feat(windows): 支持 MSI 主程序严格单实例启动

- 仅对带 MSI 安装标识的 Windows 主程序启用单实例门禁，Portable 与特殊运行模式保持原行为
- 重复启动通过命名事件唤醒首个窗口，并兼容 Wails 运行时尚未就绪的激活请求
- 新增并发抢占、窗口激活与安装模式测试，覆盖同一安装仅保留一个主实例

internal/app/update_install_mode.go

@@ -31,6 +31,12 @@ func resolveCurrentUpdateInstallMode() updateInstallMode {
 	return resolveUpdateInstallModeForExecutable(runtime.GOOS, updateResolveInstallTarget())
 }
 
+// IsWindowsMSIInstallExecutable reports whether executablePath belongs to a
+// GoNavi MSI installation. The marker is packaged next to the stable MSI exe.
+func IsWindowsMSIInstallExecutable(goos string, executablePath string) bool {
+	return resolveUpdateInstallModeForExecutable(goos, executablePath) == updateInstallModeMSI
+}
+
 func resolveUpdateInstallModeForExecutable(goos string, executablePath string) updateInstallMode {
 	if !strings.EqualFold(strings.TrimSpace(goos), "windows") {
 		return updateInstallModeUnknown