feat: add scroll top mask, unify page top spacing and docs

src/pages/diy/stickerEdit/index.tsx

@@ -8,6 +8,7 @@ import { useThemeContext } from '../../../context/ThemeContext'
 import { useSafeArea } from '../../../hooks/useSafeArea'
 import { useStatusBar } from '../../../hooks/useStatusBar'
 import ThemedPageMeta from '../../../components/ThemedPageMeta'
+import ScrollTopMask from '../../../components/ScrollTopMask'
 import BottomActionBar from '../../../components/BottomActionBar'
 
 /* ============================================================
@@ -311,9 +312,10 @@ export default function StickerEditPage() {
   return (
     <View className={`theme-${resolvedTheme}`}>
       <ThemedPageMeta />
+      <ScrollTopMask title="编辑贴纸" targetSelector=".edit-header" showBack />
       <View className='sticker-edit-page'>
         {/* Header */}
-        <View className='edit-header' style={{ paddingTop: `${safe.headerPaddingTop}px` }}>
+        <View className='edit-header' style={{ paddingTop: `${safe.statusBarHeight + 12}px` }}>
           <Text className='edit-back' onTap={() => Taro.navigateBack()}>←</Text>
           <Text className='edit-title'>编辑贴纸</Text>
           <Text className='edit-save' onTap={handleSave}>保存</Text>