fix: add missing PageShell component for production build

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend-dapp/src/components/ui/PageShell.tsx

@@ -0,0 +1,20 @@
+interface PageShellProps {
+  title: string
+  subtitle?: string
+  badge?: string
+  wide?: boolean
+  children: React.ReactNode
+}
+
+export default function PageShell({ title, subtitle, badge, wide, children }: PageShellProps) {
+  return (
+    <div className={`ui-animate-in ${wide ? 'ui-page-wide' : 'ui-page'}`}>
+      <header className="mb-8">
+        {badge && <div className="ui-badge mb-3 w-fit">{badge}</div>}
+        <h1 className="ui-hero-title">{title}</h1>
+        {subtitle && <p className="ui-hero-sub">{subtitle}</p>}
+      </header>
+      {children}
+    </div>
+  )
+}