收口统一弹窗关闭按钮

新增 PlatformModalCloseButton pixel 变体承接像素风关闭入口

将 UnifiedModal 头部关闭按钮迁移到 PlatformModalCloseButton

补充平台态和像素态关闭按钮测试

更新 PlatformUiKit 文档和 Hermes 决策记录

src/components/common/PlatformModalCloseButton.tsx

@@ -7,6 +7,7 @@ type PlatformModalCloseButtonVariant =
   | 'floating'
   | 'floatingPlain'
   | 'platformIcon'
+  | 'pixel'
   | 'editorDark';
 
 type PlatformModalCloseButtonProps = Omit<
@@ -30,7 +31,9 @@ const PLATFORM_MODAL_CLOSE_BUTTON_CLASS_BY_VARIANT: Record<
     'absolute right-3 top-3 z-10 flex h-8 w-8 items-center justify-center rounded-full bg-white/80 text-[#ff4056] shadow-sm',
   floatingPlain:
     'absolute right-3 top-2 z-10 flex h-8 w-8 items-center justify-center rounded-full text-[#ff4056]',
-  platformIcon: 'platform-icon-button',
+  platformIcon: 'platform-icon-button disabled:cursor-not-allowed disabled:opacity-45',
+  pixel:
+    'rounded-full border border-white/10 bg-black/20 p-2 text-zinc-400 transition-colors hover:text-white disabled:cursor-not-allowed disabled:opacity-45',
   editorDark:
     'platform-modal-close-button--editor-dark rounded-full border border-white/10 bg-white/5 p-2 text-zinc-300 transition hover:bg-white/10 hover:text-white',
 };