style: 首页整体尺寸缩小约 67%

- useHomeResponsive: 标题尺寸 4xl→2xl，正文 xl→md
- HomePage: VStack/SimpleGrid 间距缩小
- HeroHeader: spacing/padding 缩小，maxW 调整
- FeaturedFeatureCard: 图标、标题、按钮尺寸缩小
- FeatureCard: 卡片高度 180→120px，整体元素尺寸缩小

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/hooks/useHomeResponsive.ts

@@ -18,21 +18,21 @@ export const useHomeResponsive = (): ResponsiveConfig => {
   });
 
   const headingSize = useBreakpointValue({
-    base: 'xl',
-    md: '3xl',
-    lg: '4xl'
+    base: 'lg',
+    md: 'xl',
+    lg: '2xl'
   });
 
   const headingLetterSpacing = useBreakpointValue({
-    base: '-1px',
-    md: '-1.5px',
-    lg: '-2px'
+    base: '-0.5px',
+    md: '-1px',
+    lg: '-1.5px'
   });
 
   const heroTextSize = useBreakpointValue({
-    base: 'md',
-    md: 'lg',
-    lg: 'xl'
+    base: 'xs',
+    md: 'sm',
+    lg: 'md'
   });
 
   const containerPx = useBreakpointValue({