Polish settings UI, add tooltips, replace timeAgo with date-fns

Clean up settings section design: consolidate backup cards, add
hover-reveal actions with tooltips, improve icon sizing across
components, and replace custom timeAgo helper with date-fns
formatDistanceToNow in webhook card.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/(pages)/dashboard/_components/library-section.tsx

@@ -21,7 +21,7 @@ export async function LibrarySection({ userId }: { userId: string }) {
   return (
     <FeedSection
       title="In Your Library"
-      icon={<IconSparkles size={20} className="text-primary" />}
+      icon={<IconSparkles className="size-5 text-primary" />}
     >
       <TitleGrid items={items} />
     </FeedSection>