收口前端平台组件能力

新增 PlatformAsyncStatePanel 统一 profile 异步状态骨架
扩展 PlatformSegmentedTabs 支持滚动 tab 并接入创作入口与发现页
统一 PixelCloseButton 复用 PlatformModalCloseButton 像素关闭能力
抽取平台入口泥点前置提示弹层并收紧阻断语义
补充组件收口文档与共享决策记录

src/components/common/PlatformSegmentedTabs.test.tsx

@@ -162,3 +162,31 @@ test('supports auth-style tab semantics with underline tone', () => {
 
   expect(onChange).toHaveBeenCalledWith('password');
 });
+
+test('supports scroll layout for horizontal tabs', () => {
+  render(
+    <PlatformSegmentedTabs
+      items={[
+        { id: 'recent', label: '最近创作' },
+        { id: 'rpg', label: '文字冒险' },
+        { id: 'jump-hop', label: '跳一跳' },
+      ]}
+      activeId="recent"
+      onChange={vi.fn()}
+      layout="scroll"
+      semantics="tabs"
+      ariaLabel="创作入口页签"
+      frame="bare"
+      surface="transparent"
+      className="pb-1"
+    />,
+  );
+
+  const tablist = screen.getByRole('tablist', { name: '创作入口页签' });
+
+  expect(tablist.className).toContain('flex');
+  expect(tablist.className).toContain('overflow-x-auto');
+  expect(tablist.className).toContain('scrollbar-hide');
+  expect(tablist.className).not.toContain('grid-cols-2');
+  expect(tablist.className).toContain('pb-1');
+});