固定客户端dev服务并支持官网多平台下载

移除服务器选择并按来源隔离登录凭据
新增官网客户端下载入口和匿名平台聚合接口
根据发布清单自动展示Windows与macOS首装包
补齐Mac首装元数据和上传顺序校验
同步定向测试与下载发布规范

src/components/platform-entry/PlatformEntryActiveFlowShell.tsx

@@ -30,6 +30,7 @@ import { useAuthUi } from '../auth/AuthUiContext';
 import { FLOATING_FEEDBACK_FORM_URL } from '../common/floatingFeedbackEntryModel';
 import { PlatformActionButton } from '../common/PlatformActionButton';
 import { PlatformSubpanel } from '../common/PlatformSubpanel';
+import { ClientDownloadEntry } from '../creation-home/ClientDownloadEntry';
 import {
   PlatformActiveMobileWelcomeDialog,
   shouldOpenActiveMobileWelcomeDialog,
@@ -494,7 +495,7 @@ export function PlatformEntryFlowShellImpl({
             </aside>
 
             <div className="platform-desktop-main flex min-w-0 flex-1 flex-col">
-              <header className="platform-desktop-topbar flex min-h-16 shrink-0 items-center justify-between gap-1 px-4 sm:gap-3 sm:px-6">
+              <header className="platform-desktop-topbar flex min-h-16 shrink-0 flex-wrap items-center justify-between gap-1 gap-y-2 px-4 py-2 sm:flex-nowrap sm:gap-3 sm:px-6 sm:py-0">
                 <div className="min-w-0 shrink-0 lg:hidden">
                   <ActivePlatformBrand />
                 </div>
@@ -534,7 +535,8 @@ export function PlatformEntryFlowShellImpl({
                   </form>
                 </div>
 
-                <div className="platform-desktop-topbar__actions flex shrink-0 items-center gap-1 sm:gap-2 lg:gap-3">
+                <div className="platform-desktop-topbar__actions flex max-w-full shrink-0 flex-wrap items-center gap-1 sm:flex-nowrap sm:gap-2 lg:gap-3">
+                  <ClientDownloadEntry />
                   {isAuthenticated ? (
                     <PlatformMudPointWalletEntry
                       variant={isDesktopLayout ? 'desktop' : 'mobile'}