feat(dcauth): 移除机器码，改用纯设备码认证

- DCAuth 协议升级到 v2，签名原文只含设备码；客户端 2.0.0，旧版本返回 426
- 删除客户端机器码采集、后端 machine_code_* 字段与日志、后台机器码展示
- 102 迁移在生产执行前直接改为无机器码结构；SQL 守卫仅放行该文件
- Mock 短信不启用每日限额；修复慢电脑首次启动的协议转发竞态
- 新增 macOS DCAuth.app 打包脚本，注册 dcauth:// 协议，浏览器可直接唤起

apps/dcauth/ui_windows.go

@@ -191,6 +191,7 @@ var (
 	trayData            notifyIconData
 	trayAdded           bool
 	runtimeIdentity     identity
+	identityReady       bool
 	authorizationActive bool
 	windowProcedure     = syscall.NewCallback(dcauthWindowProc)
 )
@@ -209,16 +210,14 @@ func runClient(protocolArg string) {
 		if forwardToRunningInstance(protocolArg) {
 			return
 		}
-		showError("DCAuth 启动失败", "已有 DCAuth 实例正在启动，但暂时无法连接，请稍后重试。")
-		return
+		firstInstance, err = acquireSingleInstance()
+		if err != nil || !firstInstance {
+			showError("DCAuth 启动失败", "DCAuth 已在运行但暂时没有响应。请在任务管理器中结束 DCAuth.exe 后重试。")
+			return
+		}
 	}
 
 	registerProtocol()
-	runtimeIdentity, err = loadOrCreateIdentity()
-	if err != nil {
-		showError("DCAuth 初始化失败", err.Error())
-		return
-	}
 	if err := createHiddenWindow(); err != nil {
 		showError("DCAuth 启动失败", err.Error())
 		return
@@ -228,10 +227,20 @@ func runClient(protocolArg string) {
 		return
 	}
 
+	runtimeIdentity, err = loadOrCreateIdentity()
+	if err != nil {
+		removeTrayIcon()
+		showError("DCAuth 初始化失败", err.Error())
+		destroyWindow.Call(mainWindow)
+		mainWindow = 0
+		return
+	}
+	identityReady = true
+
 	if protocolArg != "" {
 		handleAuthorization(protocolArg)
 	} else {
-		showTrayBalloon("DCAuth v"+clientVersion+" 已在后台运行", "双击托盘图标可查看版本、设备码和机器码。")
+		showTrayBalloon("DCAuth v"+clientVersion+" 已在后台运行", "双击托盘图标可查看版本和设备码。")
 	}
 
 	runMessageLoop()
@@ -279,16 +288,16 @@ func acquireNamedMutex(name string) (uintptr, bool, error) {
 }
 
 func forwardToRunningInstance(protocolArg string) bool {
-	for attempt := 0; attempt < 100; attempt++ {
-		if postToRunningInstance(protocolArg) {
-			return true
+	for attempt := 0; attempt < 300; attempt++ {
+		if hwnd := findRunningInstanceWindow(); hwnd != 0 {
+			return sendToRunningInstance(hwnd, protocolArg)
 		}
 		sleep.Call(100)
 	}
 	return false
 }
 
-func postToRunningInstance(protocolArg string) bool {
+func findRunningInstanceWindow() uintptr {
 	classPtr, _ := syscall.UTF16PtrFromString(windowClassName)
 	titlePtr, _ := syscall.UTF16PtrFromString(windowTitle)
 	hwnd, _, _ := findWindowW.Call(
@@ -297,12 +306,13 @@ func postToRunningInstance(protocolArg string) bool {
 	)
 	runtime.KeepAlive(classPtr)
 	runtime.KeepAlive(titlePtr)
-	if hwnd == 0 {
-		return false
-	}
+	return hwnd
+}
+
+func sendToRunningInstance(hwnd uintptr, protocolArg string) bool {
 	if protocolArg == "" {
-		postMessageW.Call(hwnd, showWindowMessage, 0, 0)
-		return true
+		result, _, _ := postMessageW.Call(hwnd, showWindowMessage, 0, 0)
+		return result != 0
 	}
 
 	encoded, _ := syscall.UTF16FromString(protocolArg)
@@ -387,6 +397,9 @@ func runMessageLoop() {
 func dcauthWindowProc(hwnd, msg, wParam, lParam uintptr) uintptr {
 	switch uint32(msg) {
 	case wmCopyData:
+		if !identityReady {
+			return 0
+		}
 		data := (*copyDataStruct)(unsafe.Pointer(lParam))
 		if data != nil && data.DwData == copyDataMagic && data.CbData > 0 && data.LpData != 0 {
 			count := int(data.CbData / 2)
@@ -396,12 +409,18 @@ func dcauthWindowProc(hwnd, msg, wParam, lParam uintptr) uintptr {
 		}
 		return 0
 	case showWindowMessage:
-		showDeviceInfo()
+		if identityReady {
+			showDeviceInfo()
+		}
 		return 0
 	case trayCallbackMessage:
 		switch uint32(lParam) {
 		case wmLButtonDblClk:
-			showDeviceInfo()
+			if identityReady {
+				showDeviceInfo()
+			} else {
+				showTrayBalloon("DCAuth 正在初始化", "设备信息准备完成后即可查看。")
+			}
 		case wmRButtonUp, wmContextMenu:
 			showTrayMenu(hwnd)
 		}
@@ -497,7 +516,11 @@ func showTrayMenu(hwnd uintptr) {
 
 	switch command {
 	case trayMenuDeviceInfo:
-		showDeviceInfo()
+		if identityReady {
+			showDeviceInfo()
+		} else {
+			showTrayBalloon("DCAuth 正在初始化", "设备信息准备完成后即可查看。")
+		}
 	case trayMenuExit:
 		destroyWindow.Call(hwnd)
 	}
@@ -505,12 +528,11 @@ func showTrayMenu(hwnd uintptr) {
 
 func showDeviceInfo() {
 	text := fmt.Sprintf(
-		"版本：v%s\n\n设备码：%s\n机器码：%s\n\nDCAuth 正在后台运行。浏览器登录时只会打开一个确认窗口。\n设备码和机器码已复制到剪贴板。",
+		"版本：v%s\n\n设备码：%s\n\nDCAuth 正在后台运行。浏览器登录时只会打开一个确认窗口。\n设备码已复制到剪贴板。",
 		clientVersion,
 		runtimeIdentity.deviceID,
-		runtimeIdentity.machineCode,
 	)
-	copyToClipboard(runtimeIdentity.deviceID + "\n" + runtimeIdentity.machineCode)
+	copyToClipboard(runtimeIdentity.deviceID)
 	showInfo("DCAuth v"+clientVersion+" 设备信息", text)
 }
 
@@ -543,11 +565,10 @@ func handleAuthorization(raw string) {
 	if !confirm(
 		"DCAuth v"+clientVersion+" · "+app.DisplayName+" 本机登录确认",
 		fmt.Sprintf(
-			"是否允许使用本机设备登录「%s」？\n\n客户端版本：v%s\n设备码：%s\n机器码：%s\n\n点击“确定”允许本次登录，点击“取消”拒绝。",
+			"是否允许使用本机设备登录「%s」？\n\n客户端版本：v%s\n设备码：%s\n\n点击“确定”允许本次登录，点击“取消”拒绝。",
 			app.DisplayName,
 			clientVersion,
 			runtimeIdentity.deviceID,
-			runtimeIdentity.machineCode,
 		),
 	) {
 		return