Reduce dialog width

Reduce the width of the welcome and expense dialogs to improve the visibility of rounded corners.

src/components/onboarding/WelcomeDialog.tsx

@@ -31,7 +31,7 @@ const WelcomeDialog: React.FC<WelcomeDialogProps> = ({ open, onClose }) => {
 
   return (
     <Dialog open={open} onOpenChange={() => handleClose()}>
-      <DialogContent className="sm:max-w-md">
+      <DialogContent className="w-[90%] max-w-sm mx-auto">
         <DialogHeader>
           <DialogTitle className="text-center text-2xl text-neuro-income mb-2">
             젤리의 적자탈출에 오신 것을 환영합니다!