fix(ui): widen scroll-mt on about and privacy anchors so the sticky header does not occlude the section start

Both pages anchored their sections at scroll-mt-20 (80 px). The sticky
header pads safe-area-inset-top (~47 px on a notch device) plus py-3
plus an inner min-h-11 link, landing around 115 px — past the 80 px
offset. Lifting to scroll-mt-28 (112 px) clears the header on every
viewport we ship to without over-padding the desktop case.

src/app/about/page.tsx

@@ -42,7 +42,7 @@ function Section({
   children: React.ReactNode;
 }) {
   return (
-    <section id={id} className="space-y-3 scroll-mt-20">
+    <section id={id} className="space-y-3 scroll-mt-28">
       <h2 className="text-xl font-semibold tracking-tight md:text-2xl">
         {title}
       </h2>

src/app/privacy/page.tsx

@@ -48,7 +48,7 @@ interface SectionProps {
 
 function Section({ id, title, children }: SectionProps) {
   return (
-    <section id={id} className="space-y-3 scroll-mt-20">
+    <section id={id} className="space-y-3 scroll-mt-28">
       <h2 className="text-xl font-semibold tracking-tight md:text-2xl">
         {title}
       </h2>