refactor: change button variant from 'ghost' to 'text' across multiple components for consistency

apps/web/src/app/(auth)/login/page.tsx

@@ -137,7 +137,7 @@ export default function LoginPage() {
   return (
     <div className="flex h-screen items-center justify-center relative">
       <Button
-        variant="ghost"
+        variant="text"
         onClick={() => router.back()}
         className="absolute top-6 left-6"
       >

apps/web/src/app/(auth)/signup/page.tsx

@@ -159,7 +159,7 @@ export default function SignUpPage() {
   return (
     <div className="flex h-screen items-center justify-center relative">
       <Button
-        variant="ghost"
+        variant="text"
         onClick={() => router.back()}
         className="absolute top-6 left-6"
       >