fix(breadcrumb+page-header): 面包屑三元素水平中心对齐 + 缩小间距

Breadcrumb 修改：
- items-baseline → items-center（水平中心线对齐）
- Home 图标外层添加 w-5 h-5 + justify-center（固定尺寸确保居中）
- 箭头添加 shrink-0 防止被压缩
- 确保 🏠 / > / 文字 三者视觉中心在同一水平线

PageHeader 修改：
- pt-16 pb-16 → pt-8 pb-12（进一步缩小与面包屑的间距）

src/components/layout/breadcrumb.tsx

@@ -14,17 +14,17 @@ interface BreadcrumbProps {
 
 export function Breadcrumb({ items }: BreadcrumbProps) {
   return (
-    <nav aria-label="breadcrumb" className="flex items-baseline gap-2 text-xs md:text-sm text-[#5C5C5C] py-3 md:py-4 leading-none">
+    <nav aria-label="breadcrumb" className="flex items-center gap-2 text-xs md:text-sm text-[#5C5C5C] py-3 md:py-4 leading-none">
       <StaticLink
         href="/"
-        className="inline-flex items-center hover:text-[#C41E3A] transition-colors"
+        className="inline-flex items-center justify-center hover:text-[#C41E3A] transition-colors w-5 h-5"
         aria-label="返回首页"
       >
         <Home className="w-4 h-4" />
       </StaticLink>
       {items.map((item, index) => (
-        <div key={index} className="flex items-baseline">
-          <ChevronRight className="w-3.5 h-3.5 text-[#CCCCCC] mx-1" />
+        <div key={index} className="flex items-center">
+          <ChevronRight className="w-3.5 h-3.5 text-[#CCCCCC] mx-1 shrink-0" />
           <StaticLink
             href={item.href}
             className="hover:text-[#C41E3A] transition-colors"

src/components/ui/page-header.tsx

@@ -31,7 +31,7 @@ export function PageHeader({ badge, title, description, className = '' }: PageHe
       />
       <SubtleDots color="#C41E3A" count={6} />
       
-      <div className="container-wide relative z-10 pt-16 pb-16" ref={ref}>
+      <div className="container-wide relative z-10 pt-8 pb-12" ref={ref}>
         <motion.div
           initial={{ opacity: 0, y: 20 }}
           animate={isInView ? { opacity: 1, y: 0 } : {}}