feat(dcauth): 新增常驻托盘客户端与版本显示

Windows 改为单实例托盘常驻，协议唤起只弹一个确认窗口；补充 macOS 后台守护进程
与客户端版本显示。

apps/frontend/src/pages/admin/AdminLoginPage.tsx

@@ -25,6 +25,9 @@ type LoginForm = {
   smsCode: string
 }
 
+const isMacPlatform =
+  typeof navigator !== 'undefined' && /Macintosh|Mac OS X|iPhone|iPad/i.test(navigator.userAgent)
+
 const brandFeatures = [
   {
     icon: <DashboardOutlined />,
@@ -54,6 +57,7 @@ export default function AdminLoginPage() {
   const [waiting, setWaiting] = useState(false)
   const [devLaunchUrl, setDevLaunchUrl] = useState('')
   const timerRef = useRef<number | null>(null)
+  const submittingRef = useRef(false)
 
   useEffect(() => {
     return () => {
@@ -94,6 +98,8 @@ export default function AdminLoginPage() {
   }
 
   async function submitLogin(values: LoginForm) {
+    if (submittingRef.current) return
+    submittingRef.current = true
     setLoading(true)
     setWaiting(false)
     try {
@@ -105,7 +111,7 @@ export default function AdminLoginPage() {
       })
       setPhoneMasked(prepared.data.phoneMasked)
       setWaiting(true)
-      setDevLaunchUrl(import.meta.env.DEV ? prepared.data.launchUrl : '')
+      setDevLaunchUrl(import.meta.env.DEV && isMacPlatform ? prepared.data.launchUrl : '')
       message.info('已发起本机验证，请在弹出的 DCAuth 窗口中确认')
       launchProtocol(prepared.data.launchUrl)
 
@@ -121,6 +127,7 @@ export default function AdminLoginPage() {
         message.error(error instanceof Error ? error.message : '登录失败')
       }
     } finally {
+      submittingRef.current = false
       setLoading(false)
       setWaiting(false)
       setDevLaunchUrl('')
@@ -128,12 +135,14 @@ export default function AdminLoginPage() {
   }
 
   async function submitLegacyLogin() {
+    if (submittingRef.current) return
     let values: Pick<LoginForm, 'username' | 'password'>
     try {
       values = await form.validateFields(['username', 'password'])
     } catch {
       return
     }
+    submittingRef.current = true
     setLoading(true)
     try {
       const response = await loginAdmin({
@@ -146,6 +155,7 @@ export default function AdminLoginPage() {
     } catch (error) {
       message.error(error instanceof Error ? error.message : '账号密码登录失败')
     } finally {
+      submittingRef.current = false
       setLoading(false)
     }
   }