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)/settings/_components/integrations-section.tsx

@@ -95,7 +95,7 @@ export function IntegrationsSection({
   return (
     <div>
       <div className="mb-3 flex items-center gap-2">
-        <IconWebhook size={16} className="text-muted-foreground" />
+        <IconWebhook className="size-4 text-muted-foreground" />
         <h2 className="text-xs font-medium uppercase tracking-wider text-muted-foreground">
           Integrations
         </h2>