feat(web): footer reads 'Signed in as <username>' with italic name

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/web/src/components/app-shell.tsx

@@ -47,8 +47,8 @@ function SignOutButton({ username }: { username: string | null }) {
     <div className="flex items-center justify-between gap-2">
       <div className="min-w-0">
         {username && (
-          <p className="text-xs text-muted-foreground truncate" aria-label="Signed in as">
-            {username}
+          <p className="text-xs text-muted-foreground truncate">
+            Signed in as <em className="italic font-medium text-foreground">{username}</em>
           </p>
         )}
       </div>