style(settings): align the mobile passkey card padding with sibling surfaces

The mobile passkey list rows used a tighter p-3 while every other card
surface in the account section uses the standard padding step. Bump to p-4
so nested card surfaces read consistently; radius stays rounded-lg.

src/components/settings/account-section.tsx

@@ -948,7 +948,7 @@ function PasskeyListSection({ isAuthenticated }: { isAuthenticated: boolean }) {
         {passkeys.map((pk) => (
           <li
             key={pk.id}
-            className="bg-card border-border rounded-lg border p-3"
+            className="bg-card border-border rounded-lg border p-4"
           >
             <div className="flex items-start justify-between gap-2">
               <div className="min-w-0 flex-1">