fix(h5): hide in-page nav titles that duplicate WeChat chrome

Keep back buttons and header layout. mini-user only hides titles on H5; partner/shop hide .app-page-title and legal titles; shared PageHeader defaults showTitle=false.

packages/shared-ui/src/PageHeader.tsx

@@ -3,11 +3,19 @@ type PageHeaderProps = {
   onBack?: () => void;
   backLabel?: string;
   right?: React.ReactNode;
+  /** 是否展示居中标题；H5 微信内默认隐藏，避免与系统标题栏重复 */
+  showTitle?: boolean;
 };
 
-export default function PageHeader({ title, onBack, backLabel = '←', right }: PageHeaderProps) {
+export default function PageHeader({
+  title,
+  onBack,
+  backLabel = '←',
+  right,
+  showTitle = false,
+}: PageHeaderProps) {
   return (
-    <header className="page-header">
+    <header className="page-header" aria-label={title}>
       <div className="page-header-side">
         {onBack ? (
           <button type="button" className="back-btn" onClick={onBack} aria-label="返回">
@@ -17,7 +25,11 @@ export default function PageHeader({ title, onBack, backLabel = '←', right }:
           <span className="page-header-spacer" />
         )}
       </div>
-      <div className="app-page-title page-header-title">{title}</div>
+      {showTitle ? (
+        <div className="app-page-title page-header-title">{title}</div>
+      ) : (
+        <div className="page-header-title page-header-title--spacer" aria-hidden="true" />
+      )}
       <div className="page-header-side page-header-side--right">{right ?? <span className="page-header-spacer" />}</div>
     </header>
   );

packages/shared-ui/src/base.css

@@ -531,6 +531,12 @@ button, input, select, textarea { font: inherit; }
   flex: 1;
 }
 
+.page-header-title--spacer {
+  font-size: 0;
+  line-height: 0;
+  min-height: 26px;
+}
+
 /* Coupon badge (ticket notch) */
 .coupon-badge {
   position: relative;